Answer:
35 quarters
Step-by-step explanation:
This situation has two unknowns - the total number of dimes and the total number of quarters. Because we have two unknowns, we will write a system of equations with two equations using the two unknowns.
is an equation representing the total number of coins
is an equation representing the total value in money based on the number of coin. 0.10 and 0.25 come from the value of a dime and quarter individually.
We write the first equation in terms of q by subtracting it across the equal sign to get 
. We now substitute this for d in the second equation.
After simplifying, we subtract 6 across and divide by the coefficient of q.
We now know of the 60 coins that 35 are quarters. To find the total value of the quarters, we multiply 35 by 0.25 and find 8.75.
408 round to the nearest tenth: 410
Girls: 81
boys: 75
4x +6 = 156
4x = 150
x = 37.5
2x = 75
girls: 75 + 6
boys: x
X = 4y
3x - y = 70
substitute the x in the second equation with the other half of the first equation.
3(4y) - y = 70
12y - y = 70
11y = 70
y = 6.36 repeating, or 6 4/11
now use this to solve first equation
x = 4 (6 4/11)
x = 25.45 repeating
done
