Q: X's income equals 3/4 of Y's income, while X's expenses equal 4/5 of Y's expenses. Find the ratio of X's savings to Y's savings if X's income is 9/10 of Y's spending.
Let X’s income be 3k then Y’s income is 4k.
Let X’s expenditure be 4g then Y’s expenditure is 5g.
But 3k = 9/10 (5g) or k = 3/2g
X’s saving/Y’s saving = (3k - 4g)/(4k - 5g)
[3 (3 / 2g) - 4g]/[ 4(3 / 2g) - 5g] = 1/2
X’s saving : Y’s saving = 1 : 2