Therefore, A’s one day work + B’s one day work = (A + B)’s one day workĪs, x ≠ 2, because if x = 2, then A alone can finish work in (2 – 6) = – 4 days which is not possible. Given that (A + B) can finish the work in 4 days. Therefore, A alone can finish the work in (x – 6) days If both A and B together can finish the work in 4 days, find the time taken by B to finish the work.Įxplanation: Let B alone finish the work in x days. A takes 6 days less than B to finish a piece of work. Given that at t minutes past 2 PM, the time needed by the minute’s hand of a clock to show 3 PM was found to be 3 minutes less than t 2/4minutesġ5.
Then t is equal toĮxplanation: We know that the time between 2 PM to 3 PM = 1 hr = 60 min Satvik observed that in a clock, the time needed by the minute hand of a clock to show 3 PM was found to be 3 min less than t 2/4 minutes at t minutes past 2 PM.
Therefore original average speed is 42 km/hr.ġ4. Since speed cannot be negative, so we ignore –3, If it takes 3 hours to complete the total journey, what is its original average speed? A train travels at a certain average speed for a distance of 63 km and then travels a distance of 72 km at an average speed of 6 km/h more than its original speed. Rohini had scored 10 more marks in her mathematics test out of 30 marks, 9 times these marks would have been the square of her actual marks. If one root is reciprocal of other, then product of roots is:ġ2. If the one root of the equation 4x 2 – 2x + p – 4 = 0 be the reciprocal of other. If equation has no real roots then discriminant of the equation must be less than zero.ġ1. If x 2 (a 2 + b 2) + 2x (ac + bd) + c 2 +d 2 = 0 has no real roots, then Since y cannot be negative as negative square root is not real so y = 3.ġ0. Let the consecutive integral multiple be 5n and 5(n + 1) where n is a positive integer.Īs n is a positive natural number so n = – 4 will be discarded. The product of two successive integral multiples of 5 is 300. Since the number is natural, so we consider only positive value.Ħ. A natural number, when increased by 12, equals 160 times its reciprocal. If 1/2 is a root of the equation x 2 + kx – (5/4) = 0 then the value of k isĪs one root of the equation x 2 + kx – (5/4) = 0 is 1/2Īlso Check: CBSE Class 10 Science Important MCQs: All Chaptersĥ. Hence the given equation can be solved by adding and subtracting 3/16.Ĥ.
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