maths quiz?

Question

I had a go at this quiz but some of the questions were to hard for me so if your good at maths i would appreteate it if u helped me out thanks.

these are the questions i could not get:
1. This Christmas, your brother Jack is twice as old as your sister Jen. The sum of Jack’s age and three times Jen’s age is 35. How old is Jen?4 years old

2. Dana needs 300 Christmas lights with equal amounts of each of her 4 selected colours. She already has 32 red, 26 green, 9 yellow and no blue. How many more of each colour does Dana need to buy?
If the bulbs cost 25 pence and you get 20% off if you purchase 50 or more of the same colour and 30% off if you purchase 60 or more of one colour, how much does Dana need to spend? Show your working out.

3. Parents donated fudge for the Christmas fund raiser for your classroom. 40 pounds of chocolate fudge sold for £2.15 per pound and vanilla fudge sold for £1.90 per pound. Your class made £158.20. How many pounds of fudge were sold?

4. Justin is making snowballs to build a fort in the Christmas holidays. Justin can build 15 snowballs in an hour but 2 snowballs melt every 15 minutes. How long will it take him to build 210 snowballs?

5. You have 15 meters of ribbon for your Christmas gift boxes. Each box gets the same amount of ribbon. How much ribbon will each of your 20 gift boxes get?

6. You finally have your Christmas shopping money! You put £2.00 away in January, £4.00 away in February, £8.00 away in March, £16.00 away in April and followed this savings pattern through to December. How much money do you have to shop with?

Answer 1

1. Why did you put "4 years old" at the end? Anyway, the answer is, Jen is 7. Jack's age (B) (for "brother") equals twice Jen's age (S for sister).

B = 2S
B + 3S = 35

Substitute 2S for B in the second equation:
(2S) + 3S = 35
5S = 35
S = 7

2. First part:
300/4 = 75, so she needs 75 of each, total.

75 - 32 = She needs 43 red
75 - 26 = She needs 49 green
75 - 9 = She needs 66 yellow
75 - 0 = She needs 75 blue

Second part:

(I'm from the U.S, there are 100 pence in a pound, right? I
have to use the $ sign because of my keyboard.)

43 red X 25 pence = $10.75
49 green X 25 pence = $12.25
66 yellow X 25 pence = $16.50 - 30% = 16.5 X .7 = $11.55
75 blue X 25 pence = $18.75 X .7 = 13.125 = $13.13

10.75 + 12.25 + 11.55 + 13.13 = $47.68

3. 40 Lb X 2.15 POUNDS (money) = 86 pounds from chocolate fudge.

158.20 total money - 86 = 72.20 from vanilla fudge.

72.20 / 1.90 per Lb = 38 Lbs of vanilla fudge sold.

38 + 40 = 78 Lbs fudge sold total.

4. First, 15 minute periods would occur 4 times in 1 hour. So each hour, it would be:

15 snowballs per hour - 8 snowballs melted per hour = 7 net snowballs per hour.

(I won't even bother wondering how there's snow outside at all, if the snowballs are melting like that.)

210 snowballs / 7 per hour = 30 hours total.

5. Assuming you need to use ALL of the ribbon:

20 gift boxes / 15 meters of ribbon = 4/3 of a meter.
Or you could say, 4/3 of a meter X 39 inches per meter = 52 inches.

Let me know by "additional details" editing if you need another format.

6. The pattern is of course doubling the additional money each month. You could just add it up, but I'm lazy, so I'll use binary numbers.

In January, the total is 2.00, or 10 in binary.
February, it's January plus 4.00, or 110 in binary.
1110 for March.
11110 for April.
1111111111110 for December (12 ones followed by a zero, written in binary.)

Now I enter that into the built-in calculator on a windows:

Total money is 8190 pounds. Wow!

With all that money, you're getting me a Christmas present, right? :)

Answer 2

Let me try the first one. Call Jen's age x, that means that Jack's age is 2x. We are told that Jack's age plus three times Jen's age equals 35, which we write as:

2x+3x=35, or 5x=35 and x=7. If Jen is 7, Jack is 14, and in fact, 14 + 3x7 = 35. So I am with you if you could not get the answer of 4!!!

And let's try the snowball problem...your fifth. Let's look at the net snowball production per hour. If he makes 15 per hour, but 2 melt every 15 minutes, that means that 8 snowballs melt each hour, so he has 7 usable snowballs after an hour. At this rate, it will take him 30 hours to build the fort. Well, if 2 snowballs melt each 15 minutes, how confident are you that a snowball made in the first hour would survive to the 30th hour...I am skeptical...I don't think these puzzle makers are very adept at snow fort construction!!!

Hope this helps

Answer 3

#1) 35 divided by 3 = 11.666667
divide that figure by 2 to find Jacks age.

Jen is 11 years old but you could round it to 12 years old.

#2) You need 300 bulbs in total... divide this number by 4 (as there are four colours) to get the total of how many bulbs you would need for each colour.

You want 75 bulbs each of the four colours so you would need to buy:
43 red
49 green
66 yellow
75 blue
bulbs to get equal amounts for all four colours.

Red! (43 bulbs at 25p each) 43 * 0.25= £10.75
Green! (49 bulbs at 25p each) 49 * 0.25= £12.25
Yellow! (66 bulbs at 25p each) 66 * 0.25= £16.50
Blue! (75 bulbs at 25p each) 75 * 0.25= £18.75

You won't get a 20% discount but you will get a 30% discount when you buy yellow and blue bulbs.
To work out 30% break it down and work out 10% first. To do this, move the decimal point once to the left.

Yellow! 10% of £16.50 = £1.65
Blue! 10% of £18.75 = £1.87
You want 30% so you multiply the total three times.

Yellow! £1.65 * 3= £4.95
Blue! £1.87 * 3= £5.61

Add the total cost of all of the bulbs before you subtract the discounts.

10.75 + 12.25 + 16.50 + 18.75 = 58.25
i.e £58.25

Add both discounts together.. 4.95 + 5.61 =10.56
£10.56

You need to minus both of the discounts £10.56 (30% discount each) from her original total £58.25(without discount) which equals: £47.69

£47.69 is the amount she needs to spend.

#3) Multiply £2.15 by 40 = £86
Minus £86 from £158.20 = £72.20
Divide £72.20 by £1.90 = 38

Add 38 and 40 together to get the total amount of pounds of fudge sold which is 78 .

#4) (2 snowballs per 15mins multiplied by 4 to get how many snowballs melt per hour.) 2 * 4 = 8
8 snowballs per hour multiplied by 15 = 120 snowballs melted within 15 hours.

Answer 4

144 is the answer. 2+3=10 which means 2+3=5 5*2=10 7+2=63 7+2=9 9*7=63 now 9+7=? 9+7=16 16*9=144

Answer 5

1. Jen's age = x ==> Jack's age = 2x
The sum of Jack's age and three times Jen's age is 35
=> 2x + 3x = 35
=> x = 7
=> Jen is 7 years old

Answer 6

Yen has the age x. Jack has the age 2x.
We also know 2x+ 3x=35
5x=35

x=7 you see!

The other questions can be solved in some way like this.

Answer 7

Wow! Just reading the answers to your questions! About the Bs and Cs and X equals (forgotten already)???? you just reminded me why i never liked school. I know this answer is absolutely of no use to you.