Question

A took 15 seconds to cross a rectangular field
diagonally walking at the rate of 52 m/min and
B took the same time to cross the same field
along its sides walking at the rate of 68 m/min.
The area of the field is:
(a) 52 m2 (b) 40 m2
(c) 61 m2 (d) 60 m2

Answer 1

Distance travelled by A in 15 s = 52×1560=13 m52×1560=13 m

Therefore, Diagonal of the field = 13 m

l2+b2−−−−−√=13l2+b2=13

l2+b2=169l2+b2=169

Distance travelled by B in 15 s

= 68×1560=17 m68×1560=17 m

= l + b = 17 m

On solving Eqs. (i) and (ii)

(l+b)2=l2+b2+2ab(l+b)2=l2+b2+2ab

=> 289 = 169 + 2lb

=> 120 = 2lb

=> lb = 60

Therefore, Area = 60 sq. cm