Question

if intrest of bank is increased from 5% to 6% per annum Rajesh deposit 1500 more into account if annual intrest was now 120 more than before find orignal deposit. ​

Answer 1

let principal be p amount originally deposited

original si = pnr

si = p×1×5% =0.05p

p= si/0.05 ----A

si + 120 = p×1×6% = 0.06p

p = si+120 /0.06 ------B

rhs of A= rhs of B

si/0.05 = (si+120)/0.06

0.06/0.05 = (si+120)/si

1 +1/5 = 1+ 120/si

si = 600

p= 600/0.05 =12000/-