Question
Two trains of equal lengths take 20 seconds and 30
seconds respectively to cross a telegraph post. If the length of each train be 240 metres, in what time will they cross each other travelling in opposite direction?Solution
Speed of the first train = [240/20] m/sec = 12 m/sec Speed of the second train = [240/30] m/sec = 8 m/sec Speed = (12 + 8) m/sec = 20 m/sec Required time = (240 + 240)/20 sec = 24 sec
Evaluate:
β729 + β49 - β16 + 1/β64
Simplify:

(1/5)(40% of 800 β 120) = ? Γ 5
2/5 of 3/4 of 7/9 of 7200 = ?
`sqrt(5476)` + 40% of 1640 = ? `xx` 4 - 2020
? = (22% of 25% of 60% of 3000) + 21
Determine the simplified value of the given mathematical expression.
(342 β 20% of 5280) = ? Γ· 3
β157464 =?