exam Maths Puzzle

Ann invested a certain sum of money in a bank that paid simple interest. The amount grew to $240 at the end of 2 years. She waited for another 3 years and got a final amount of $300. What was the principal amount that she invested at the beginning?

Read Solution (Total 1)

$200
If Amount invested=p, time(in yr)=t, rate(in %)=r ,then
After 2 years, p+(p*2*r/100)=240 or 100p+2pr=24000 ---(i) &
After 5 years, p+(p*5*r/100)=300 or 100p+5pr=30000 ---(ii)
Solving (i) & (ii), pr=2000
Substituting value of pr in (i),100p+4000=24000, p=200
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exam Other Question

Shawn invested one half of his savings in a bond that paid simple interest for 2 years and received $ 550 as interest. He invested the remaining in a bond that paid compound interest, interest being compounded annually, for the same 2 years at the same rate of interest and received $605 as interest. What was the value of his total savings before investing in these two bonds? Peter invested a certain sum of money in a simple interest bond whose value grew to $300 at the end of 3 years and to $ 400 at the end of another 5 years. What was the rate of interest in which he invested his sum?