A lent Rs. 5000 to B for 2 years and Rs. 3000 to C for 4 years on simple interest at the same rate of interest and received Rs. 2200 in all from both of them as interest. The rate of interest per annum is:  Choose the correct choice from the following choices.
A) 5 %	B) 10 %	C) 7 %	D) 8 %	E) 9 %

Rationale: "explanation : let the rate of interest per annum be r % simple interest for rs . 5000 for 2 years at rate r % per annum + simple interest for rs . 3000 for 4 years at rate r % per annum = rs . 2200 ⇒ 5000 × r × 2 / 100 + 3000 × r × 4 / 100 = 2200 ⇒ 100 r + 120 r = 2200 ⇒ 220 r = 2200 ⇒ r = 10 i . e , rate = 10 % . answer : option b"
Answer: B