Basir’s working hours per day were increased by 15% and his wages per hour were increased by 20%. By how much per cent did his daily earings increase?

Increment in working hour = 15%

Increment in wages = 20%

Let the working hours before the increment be 10 hours and daily wages per hour be Rs.10.

Daily wages of Basir = 10 $$\times$$ 10 = 100

working hours after increment = 10 $$\times \frac{115}{100}$$ = 11.5

Daily wages per hours after increment = 10 $$\times \frac{120}{100}$$ = 12

Daily wages of Basir after increment = 11.5 $$\times$$ 12 = 138

Increment in his daily earning = 138 - 100 = 38

Percentage increment in his daily earning = $$\frac{38}{100} \times 100$$ = 38%