x : y = 7 : 4, x + y =88. Work out the value of x - y.

Here we use the ratios given to calculate the answer. First we sum add 7 and 4 to find total parts. 7 + 4 = 11. Then we divide 88 by 11. 88/11 = 8.This means we know that each part in the given ratio is 8.Hence, 7 x 48= 56 = x and 4 x 8 = 32 = y.Now we know the value of x and y we can calculate x - y = 56 - 32 = 24.