Explanation:
I'm assuming you meant to write 1/5 instead of 1:5
Add up all the fractions
1/4 + 3/8 + 1/10 + 1/5
20/80 + 30/80 + 8/80 + 16/80
(20+30+8+16)/80
74/80
37/40
He spends 37/40 of his income on rent, foot, clothes, insurance and other items combined.
Subtract this from 1 to find the fraction of his income he saves
1 - 37/40
40/40 - 37/40
(40-37)/40
3/40
He saves 3/40 of his monthly income.
(3/40)*8480 = 636 dollars is the amount saved every month.
