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# A sum of money invested at 5% per annum simple interest amounts to ₦285.20 aft...

### Question

A sum of money invested at 5% per annum simple interest amounts to ₦285.20 after 3 years. How long will it take the same sum to amount to ₦434.00 at 7$$\frac{1}{2}$$% per annum simple interest?

### Options

A) 10 years

B) 12 years 5month

C) 7$$\frac{1}{2}$$ years

D) 4 years

## Dicussion (1)

• Nusie Oloh

Amount= principal + PRT/100
285.20=P + P *5*3/100
285.20= 100P+15P/100
Cross multiply
28520=115P
Divide both sides by 115
P=248
Therefore how long will it take the amount 248 to 434.00
434=248/1+248*7.5*T/100
434=24800+1860T/100
Cross multiply
43400=24800+1860T
43400-24800=1860T
18600=1860T
Divide both sides by 1860
T=10
10 years