Motor boat covers a certain distance downstream in 10 hours. It covers the same distance upstream in 15 hours. If the speed of the water is 9 km/hr, then the speed of the boat in still water is:
Let the distance be ‘D’ km According to the question, Downstream speed x + y = d/10 or d = 10 (x+y) .......... (i) Upstream speed x-y = d/15 or d = 15(x-y) ........... (ii) Comparing (i) & (ii) 10(x+y) = 15(x-y) 2(x+y) = 3(x-y) 2x + 2y = 3x - 3y x = 5y Hence, y = Speed of the current = 9 km/hour. Speed of boat, x = 5 × 9 = 45 km/hr
√9604 + ∛205379 + 58% of 1500 = 520 + ?
17.8 + 3/7 of 89.6 = ?
Simplify the following expression:
(164-1)/17×15× (28+1)
?= √(4 × ∛(16 × √(4 × ∛(16 ×…… ∝)) ) )
(72× 52+ 1555 )/(79+60) = 2000 ÷ ?
√144 × √121 + 25% of 600 = ? + 256
72 x 60 x 22 x 32 =?
63 × 4 = ?2 – 1620 ÷ 5