Help!!! Math question! Please explain!?

Question

A certain grade in a school contains 96 pupils. If there are 40 boys, what is the ratio of boys to girls in this grade?

2. A man borrowed $65 from the bank for one year. He paid $7.80 in interest. What rate of interest was charged by the bank?


PLEASE HELP!

THANKS!

Answer 1

1) First find the number of girls in the school.

96 pupils - 40 boys = 56 girls

To find the ratio of 40 boys to 56 girls create a fraction,
by making the number before the word "to" in the comparison the numerator and the number arfter the word "to" the denominator. Here, the fraction is 40/56.

Express the fraction in smiplest form 5/7.

The ratio is written as 5:7.

There are 5 boys to 7 girls.

2) Rate of Interest

Interest Earned = Principal * Interest Rate (%per year) x Time (years)

$7.8 = $65 * X(Interest Rate) *1(One Year)
1 * $7.8 = $65 * X(Interest Rate)
$7.8 = $65 * X(Interest Rate)
7.8 * 1/65 = (65/1 * 1/65) * X(Interest Rate)
7.8/1 * 1/65 = 1* X(Interest Rate)
7.8/65 = X (Interest Rate)
.12 = X (Interest Rate)

To prove replace .12 into the equation

$7.8 = $65 * .12(Interest Rate) *1(One Year)
7.8 = 65 * .12 * 1
7.8 = 7.8 * 1
7.8 = 7.8

Answer 2

1. If there are 40 boys, then there are 56 girls (96-40). The ratio of boys to girls is then 40/56=5/7=71.4285714%
.2 The rate is 7.80/65=12%

Answer 3

1) there are 40 boys, so that means that there are 56 girls.
the ratio is 40 to 56, but you can reduce that.

If you divide both of them by 4, you get 10 to 14.
You can still reduce that.

If you divide them both by 2, you get 5 to 7.

This is the final ratio. there are 5 boys for every 7 girls.

As you may have figured out, a ratio is almost exactly like a fraction that needs to be reduced.

2) so it's how much OF 65 IS 7.80??

my math teacher taught me this really cool trick:

IS over OF times 100

so you'll have 7.80 (or 7.8) over 65, which is the same as 7.8 divided by 65. This will give you 0.12.

Then multiply 0.12 by 100. This gives you 12.

The interest rate charged by the bank is 12%.

Answer 4

Q#01 Its really simple just think its about your class you all are 40 boys among 96 students.You now must now know about the number of girls it is simple subtract all boys from total and the remaining we be the girls.
i.e (96-40)=46
now 96 total is devided b/w boys 40 and girls 46 so the ratio will be 40:46

Q#2) Do it like a percentage question. In this question you have to fine the rate i.e percentage .
percentage=amount /total amount *100
In this case it will be 7.8/65*100
remember for devide first then multiply.

Answer 5

1) total pupil=96
no. of boys=40
no. of girls=96-40=56
ratio=boys/girls=40/56=20/28=5/7
2) principal=65
interest=7.80
rate=interest/principal=7.8/65 * 100 = 12%

Answer 6

If there are 40 boys, then there are 96-40 = 56 girls
So ratio boys/girls = 40/56 = 5/7.

7.8 = 65x
x = 7.8/65 = .12 = 12%

Answer 7

1]

Number of pupils = 96
Number of boys = 40
Hence number of girls = 96 - 40 = 56
Hence ratio of boys to girls =
number of boys / number of girls = 40 / 56 which can be reduced to 20 / 23

Hence final ratio of boys to girls is 20 : 23



2]

Intrest = Period * Principal Amount * Rate of intrest / 100
Hence
Rate of intrest =
Interest * 100 / ( Period * Principal Amount )
= 7.80 * 100 / ( 65 * 1 )
=780 / 65
= 12

Hence rate of intrest is 12 percent per annum.

Answer 8

1. 40:(96-50)

Ratio: 40:46

2. 65/7.8

Interest rate was 8.33%