(a) Evaluate, without using mathematical tables or calculator, ((3.69 times 10^{5}) div (1.64 times 10^{-3})), leaving your answer in standard form.
(b) A man invested N20,000 in bank A and N25,000 in bank B at the beginning of the year. Bank A pays simple interest at a rate of y% per annum and B pays 1.5y% per annum. If his total interest at the end of the year from the two banks was N4,600, find the value of y.
Explanation
(a) ((3.69 times 10^{5}) div (1.64 times 10^{-3}))
= (frac{3.69}{1.64} times 10^{5 – (-3)})
= (2.25 times 10^{8})
(b) Interest from bank A : (frac{y}{100} times N20,000 = N200y)
Interest on bank B :(frac{1.5y}{100} times N25,000 = N375y)
(therefore N(200y + 375y) = N4,600)
(575y = 4,600 implies y = 8)