Question

Find the difference
between the
compound interest of second year and the
48.000 invested for 5 years at 10% per
annum compounded yearly.
(i) A sum of 50,000 is invested for 4 years at
compound interest, the rate of interest being
10%, 12%, 14% and 16% respectively for
the first 4 years. Find the total of interests
earned during first and third years.

Answer 1

Let x=0.47ˉ  (Mixed recurring decimal)

i.e. x=0.47777…(1)

Multiplying (1) by 10, to make it pure recurring decimal, we get

10x=4.7777…(2)

Further multiplying (2) by 10, we get

100x=47.777….(3)

Subtracting (2) from (3), we get

100x–10x=(47.777…)–(4.7777…)

⇒90x=43

⇒x=9043

Thus 0.47ˉ=9043

Answer 2

Area of square is 169cm2.

Let a be side of square.

Area = a2=169

a2=(13)2

[a=13 cm.]

side of square is 13 cm