The ratio of boy to girls in a class is 3 : 2. There are 15 boys in the class. How many total boys and girls are in the class?
2 answers:
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Answer:
x = 32 y = 16 z = 64
Step-by-step explanation:
x is the 1st number
y is the 2nd number
z is the 3rd number
The first number is twice the second number so
x = 2 y
The third number is twice the first number.
z = 2 x
Their sum is 112
x + y + z = 112
Plus in what we know:
x + y + z = 112
2 y + y + 2x = 112
3y + 2x = 112 Let's solve for y and subtract 2x from each side
3y = 112 - 2x Divide both sides by 3
y =
Now plug our answer back in to solve for x.
x = 2y
x = 2 ( )
x = (224 - 4x) / 3 Multiply each side by 3.
3x = 224 - 4x Add 4x to each side
3x + 4x = 224
7x = 224 Divide each side by 7
7x / 7 = 224 / 7
x = 32
Now we can solve for z.
z = 2x
z = 2 ( 32 )
z = 64
Now we can solve for the numerical value of y.
x + y + z = 112
32 + y + 64 = 112
96 + y = 112 Subtract 96 from each side.
y = 112 - 96
y = 16