Arjun & Chinky together start work and do it for 10 days and rest work is completed by Danny & ‘X’ together in 4 days. Then, in how many days ‘X’ alone can compete the work?
ATQ, we can say that Efficiency of X = ‘e’ unit/day 10 × (40 + 30) + 4 × (28 + ‘e’) = 840 10 × 70 + 4(28 + ‘e’) = 840 4(28 + ‘e’) = 840 – 700 4(28 + ‘e’) = 140 28 + ‘e’ = 140/4 28 + ‘e’ = 35 ‘e’ = 35 – 28 ‘e’ = 7 unit/days X alone complete the work in  = 840/7 = 120 Days
If 2 pens are drawn at random what is the probability that one is black and one is red ?
How many words can be formed with the letter of the word ‘FUTURE’ if repetition is not allowed?
A football team of 11 players is to be formed from 20 players including 5 defenders and 4 goal keepers. In how many different ways can a team be formed ...
If 3 pens are drawn at random what is the probability that all are black?
How many 10 digit numbers can be formed using the digits 1, 2, 0, 2, 4, 1, 2, 4, 2, 4 ?