Question
A boat takes 8 hours to travel 42 km upstream and 81 km
downstream combined. In another instance, it covers 48 km upstream and 54 km downstream in 7 hours. Determine the time the boat would need to travel 90 km in still water.Solution
Let the upstream and downstream speeds of the boat are x km/h and y km/h. So according to question: 42/x + 81/y = 8 And, 48/x + 54/y = 7 Let 1/x = a and 1/y = b So 42a + 81b = 8 ………. (i) And 48a + 54b = 7 …….. (ii) Solving (i) and (ii) we get a = 1/12 and b = 1/18 So x = 12 and y = 18 So the upstream and downstream speeds of the boat are 12 km/h and 18 km/h respectively. So the speed of the boat in still water = (12 + 18)/2 = 15 km/h So the time taken by the boat to cover 90 km in still water = 90/15 = 6 hoursÂ
2 + 5 = 36
7 + 6 = 98
6 + 4 = 62
4 + 9 = ?
Select the correct option from the given options that can make a full square. (3 of the 5 images are given below)
In each of the following questions which one of the answer figures shall complete the given question figure.
Select the figure that will come next in the following series.
Select the figure from the options that can replace the question mark (?) in the following series.
Select the figure from among the given options that can replace the question mark (?) in the following series.
Which of the given figures when placed in the 5th position would continue the series that is established by the first four figures?
Select the figure from the options that can replace the question mark (?) in the following series.
Select the figure which will come next in the following figure series.
Select the figure that will replace the question mark (?) in the following figure series.
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