The ratio of boys to girls in Jamal's class is 3:2. If four more girls join the class, there will be the same number of boys and girls. What is the number of boys in the class?

12 boys

Step-by-step explanation:

From the above question:

Number of boys = 3

Number of girls = 2

Boys: Girls

3:2

Let :

a = boys

b = girls

Hence, a : b = 3 : 2

a/b = 3/2  

Cross Multiply

2a = 3b Equation 1

a = 3b/2

If four more girls join the class, there will be the same number of boys and girls

Hence,

a: b + 4 = 3 : 3

a/b + 4 = 3/3

Cross Multiply

3a = 3(b + 4)

3a = 3b + 12 Equation (2)

From Equation 1: a = 3b/2

Substitute 3b/2 for a in Equation 2 we have:

3a = 3b + 12 Equation 2

3(3b/2) = 3b + 12

9b/2 = 3b + 12

Cross Multiply

9b = 2(3b + 12)

9b= 6b + 24

9b - 6b = 24

3b = 24

b = 8

Substitute 8 for b in Equation 1

a = 3b/2

a = 3 × 8/2

a = 24/2

a = 12

Therefore, the number of boys in the class is 12

correct choice is b

step-by-step explanation:

when you calculate the average rate of change of a function, you are finding the slope of the secant line between the two points. for the function the average rate of change from point to point can be calculated as

to find the average rate of change from day 2 to day 10, note that at day 2, 8 houses were sold, so a(2,8) and at day 10, 2 houses were sold, so b(10,2). thus,