The number of boys and girls in a class are in the ratio 4 : 7. There are 15 more girls than boys. find the number of total students in the class

The number of total students in the class is 55

Step-by-step explanation:

We will use the ratio method to solve the question

∵ The number of boys and girls in a class are in the ratio 4: 7

∵ There are 15 more girls than boys

→ That means the difference between them is 15

∵ The difference between the terms of their ratio = 7 - 4 = 3

→ By using the ratio method

→  boy  :  girl  :  difference

→  4      :  7      :  3

→  x      :  y      :  15

→ By using cross multiplication

∵ x × 3 = 4 × 15

∴ 3x = 60

→ Divide both sides by 3

∴ x = 20

∵ y × 3 = 7 × 15

∴ 3y = 105

→ Divide both sides by 3

∴ y = 35

∵ x represents the number of boys

∴ The number of boys is 20

∵ y represents the number of girls

∴ The number of girls is 35

∴ The total number of students = 20 + 35 = 55

∴ The number of total students in the class is 55

goog may have it for you

step-by-step explanation: so we look at the formula un = a + (n-1)d

un is the amount of seats

n is the nth term aka row number

a is the original sequence/row number

d is the difference between each term

so in this a=22 d=6 and n can remain as n because we are simply formjng a rule

lets put these in the equation

un=22+(n-1)(6)

this is your answer to part a

however

lets double check that this is correct, we'll try putting it into the second term

un=a+(n-1)d

u2=22+(2-1)(6)

u2=22+6

u2=28

as the question said the second row has 28 seats so now we know the formula we made is correct.

as for part b

un=a+(n-1)

its asking us to find a row with 100 seats.

remember un was the amount of seata so all we do is substitute this in.

un=100 a=22 d=6

un=a+(n-1)d

100=22+(n-1)(6)

so now we simplify to find n which is the row number.

100-22=22+(n-1)(6)-22

78=(n-1)(6)

78/6=(n-1)(6)/6

13=n-1

13+1=n-1+1

14=n

so now we know that in the 14th row there is 100 seats.

hope this and that you understood! its my first time using the app or anyone out on here : p its also me to revise so a bunch! ask more questions if you dont understand ☺