Question 698412
manju spent Rs 'a' daily and saves Rs 'b' per week from her total income

Let I be the income for 4 weeks

she spent a daily
so she spent 7a per week
so she spent 4*7a = 28a in 4 weeeks

She saves b per week
so she saves 4b in 4 weeks

For 4 weeks

 income I = 28a+4b