Question

Aman spend 2/5 of his salary for rent house 3/ 10 for food amd 1/8 for conveyances if he had 1400 rupees left himm find the expenditure for food

Answer 1

he remained: 1-2/5-3/10-1/8= 7/40 of his salary
his salary : 1400 :7 x 40= 8000 rupees
expenditure 4 food: 8000 x 1/8 =1000 rupees

Answer 2

Let the total salary be ₹x.
Spent for rent=2/5x
Spent for food=3/10x
Spent for conveyances=1/8x
Remaining=₹1400
1400+2/5x+3/10x+1/8x=x
1400=x-2/5x-3/10x-1/8x
1400=40x-16x-12x-5x/40
40×1400=40x-33x
56000=7x
x=₹8000
Money spent for food=3/10×8000
3×800
=₹2400

Hope it helps:)