Question

a father gives 1% of his monthly income to his two sons at pocket money the elders and get 80% of the total amount of money given and he spends 80% of his hair if he saves rupees 20 per month determine for the monthly income

Answer 1

Let father's incone be x rupees
Therefore, Share given to sons
=1/100*x
=x/100
Share  given to elder son
=80/100*x/100
=80x/10000
Share saved by him
=20/100*80x/10000
=1600x/1000000
Therefore,
1600x/1000000=20
1600x=20000000
x=20000000/1600
x=12,500
Therefore, father's income is Rs.12,500

Answer 2

yes like this only it will be solved