The population of a town was 3600 three years back. It is 4800 right now. What will be the population three years down the line, if the rate of growth of population has been constant over the years and has been compounding annually?

? ( 22 x r²) / 7 = 38.5
? r² =(38.5 x 7) /22
? r = 3.5 cm

? Circumference = 2 x (22/7) x 3.5 cm
= 22 cm

S.P = P.W of Rs. 2200 due 1yr hence = Rs. [(2200 x 100)/100+(10 x 1)] = Rs.2000 

Gain = Rs.(2000-1950) = Rs. 50

PW =  A m o u n t 1 + R 100 T = 2800 1 + 12 100 2   = Rs.2500 

TD = Amount - PW = 2800 - 2500 = Rs.300

P.W. = Rs. (1600 - 160) = Rs. 1440
? S.I. on Rs.1440 at 5% is Rs. 160.
? Time = [100 * 160 / 1440 * 5] = 20/9 years = [20/9 * 12] months = 27 months.

? s= (13 + 5 + 12) / 2 cm
= 15cm

s-a = 2 cm,
s-b = 10 cm and
s-c = 3 cm

? Area = ? (15 x 2 x 10 x 3 ) cm²
= 30 cm²

? (12 x h) / 2 = 30
? h = 5 cm

Let lateral side = (5y) cm and base = (4y) cm
? perimeter = 5y + 5y + 4y = 14
?y = 1

So, the sides are 5 cm , 5 cm and 4 cm

Now s= 1/2 (5 + 5 + 4) cm = 7 cm
(s-a) = 2 cm
(s-b) = 2 cm and
(s-c) = 3 cm

? Required Area = ? (7 x 2 x 2 x 3) cm²

=2?21 cm²

s = (13 + 14 + 15 ) / 2 = 21,
s-a = 8 ,
s-b = 7,
s-c= 6

? Area to be painted = ? [s(s-a) (s-b) (s-c)]
=? [21 x 8 x 7 x 6] m²
= 84 m²

? Cost of painting = Rs. (84 x 8.75) = Rs. 735

Area = ?r² = 0.49?
? r = 0.7 m

Number of revolutions = total distance / circumference
= (1.76 x 1000) / (2 x 22/7 x 0.7)
= 400

Distance travelled in 1 revolution = circumference of the wheel
= ?d
= ( 22/7 ) x 63
= 198 cm

So the distance travelled in 100 revolutions = 100 x distance travelled in 1 revolution
= 100 x 198 cm
= 19800 cm
= 198 m

Circumference of a circular = 2?r
? 2 x (22 / 7) x r = 440
? r = [440 x (7/22) x (1/2)] = 70 m

? Radius of outer circle = (70 + 14) m
= 84 m