Question

krishna deposited rs 60000 at the rate of 8% in saving account. after 5 yrs he withdrew rs 40000 and total interest of 5 yrs.how long should he keep the remaining amount to get total interest rs 28000 from the beginning...

Answer 1

Answer:

22.5 years

Step-by-step explanation:

we know that

The simple interest formula is equal to

$I=P(rt)$

where

I is the Final Interest Value

P is the Principal amount of money to be invested

r is the rate of interest  

t is Number of Time Periods

in this problem we have

$t=5\ years\\ P=Rs\ 60,000\\r=8\%=8/100=0.08$

substitute in the formula above

$I=60,000(0.08*5)$

$I=Rs\ 24,000$

Remember that

Krishna withdrew Rs 40000 and total interest

The remaining amount is

$60,000+24,000-40,000-24,000=Rs\ 20,000$

Now

we have

$t=?\ years\\ P=Rs\ 20,000\\I=\ 28,000\\r=8\%=8/100=0.08$

substitute

$28,000=20,000(0.08t)$

solve for t

$(0.08t)=28,000/20,000$

$(0.08t)=1.4$

$t=17.5\ years$

From the beginning adds 5 years

$17,5+5=22.5 \ years$