Question

a amount becomes 7000 after four years and 10000 after 8 year at a certain compund interest annually, find the principle beginning.....

Answer 1

A=P(1+R/100)^y

7000=P(1+R/100)^4

(1+R/100)^4=7000/P-------(1)

10000=7000(1+R/100)^4

10/7=(1+R/100)^4-------(2)

substitute (1) in(2)

10/7=7000/P
P=4900