What annual instalment will discharge a debt of 4,200 due in 5 years at 10% simple interest?
Options.
A) 500 per year	B) 600 per year	C) 700 per year	D) 800 per year	E) None of these
Shortcut method :   If borrowed amount be M and it is to be paid in equal instalments, then   M=na+ra/100×Y×n(n−1)/2   where Y = no. of instalments per annum   a = annual instalment   Here, M = 4200, y = 1, r = 10, n = 5, a = ?   4200 = 5a + 10a⁄100 × 5(5 - 1)⁄2   ⇒ 4200 = a[5 + 1] ⇒ 6a = 4200   ⇒ a = 700   Answer 700 per year
<result>C</result>
What annual instalment will discharge a debt of 4,200 due in 5 years at 10% simple interest?