Question
A boat takes 5 hours longer to travel 15 km upstream
than it does to travel 20 km downstream. The speed of the boat in still water is 5 km/hr. Calculate the speed of the current.Solution
Let the speed of the current be x km/hr According to the question, 15/(5 – x) – 20/(5 + x) = 5 Or, x2 + 7x – 30 = 0 Or, x2 + 10x – 3x – 30 = 0 Or, x(x + 10) – 3(x + 10) = 0 Or, (x – 3) = 0 or, (x + 10) = 0 X = -10 km/hr not possible Therefore, x = 3 km/hr Hence, option b.
‘A’ and ‘B’ invested Rs. 5000 and Rs. 4200, respectively in a business, together. After 7 months, ‘A’ withdrew 25% of his initial investment...
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If (3 × 144 – 252 ÷ 14) ÷ 18 = √1024 – x, then find the value of ‘x’.
Evaluate: (936 ÷ 12) × (225 ÷ 15) − (144 ÷ 12) × 18
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(72 × 4 – 92) ÷ 14 = ?
140% of 75 + 152 - 160 = ?
What will come in the place of question mark (?) in the given expression?
250% of...
25% of 160 × 18 = ? – 24
54% of 250 = 6 × 21 + √?
(1/2) – (3/5) + 3(1/3) = ? + (5/6)
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