Math Challenges!!!?

Question

1) How many minutes represent 10% of one full week?

2) What is the smallest odd number you can obtain from the product of four different prime numbers?

3) Two positive integers have a sum of 30 and a product of 144. Find the sum of the reciprocals of the two integers.

4) Add one straight line segment to make the mathematical sentence 5+5+5=550 a true statement

5) What is the largest possible greatest common factor of seven different two digit numbers?

Answer 1

1. 6*24*7 = 1008
2. 3*5*7*11 = 1155
3. 24,6 so 1/24 + 1/6 = 5/24
4. 5+5+5 ≠ 550
5. 14

Answer 2

1) 10 % means one number is multiplied by 0.10. So 60 minutes * 0.10 = 6 minutes. That makes 6 * 24 * 7, or 1008 minutes.

2) This one is solved by multiplying the smallest 4 different prime numbers together, but not using the 2, which will make the product even. So 3 * 5* 7* 11 will be the answer. This equals 1155.

3) This one requires listing factors of 144 until you find two of them that add to 30. Then, you will need to find the reciprocals. All of the factors of 144 are:
1 and 144
2 and 72
3 and 48
4 and 36
6 and 24
8 and 18
9 and 16
12 and 12
Of these, find the pair that adds to 30. This pair is 6 and 24.
Now find reciprocals. The reciprocal is the number "flipped over" or inverted as a fraction. 6 = 6/1 as a fraction; 24 = 24/1 as a fraction. So the final answer to this is 1/6 + 1/24 = ?
or 4/24 + 1/24 = 5/24

4) One way to do this is to turn the = sign into a not equal sign by using the slash over it. Then you can say it is true that 15 does not equal 550.

5) I'll bet this one stumped a lot of you. But the answer is actually simple. Find the largest times table of 10 or over that has 7 items under 100. This works out to 14. Ten has 9 items. Eleven has 9 items. Twelve has 8 items. Thirteen has 7 items. But 14 also has 7 items, so it is the answer. The numbers 14, 28, 42, 56, 70, 84, and 98 are 7 different two-digit numbers with a common factor of 14.

Answer 3

1. (.1)(60)(24)(7)
2. 3*5*7
3. 6, 24
Three out of 5....