Question
What was the age of Sonu 10 years ago? I. Ram
is seven years older than Sonu. II. The ratio of Ramâs present age to Sonuâs is 5:4. III. The difference between the age of Ram and that of Keshav is 12 years. The following questions are accompanied by three statements I, II and III.  You have to determine which statement(s) is/are sufficient/necessary to answer the questions.ÂSolution
Let Sonuâs present age be x years. â´ Ramâs present age is (x + 7) years From II (x + 7)/x = 5/4 â´ 4 x + 28 = 5 x x = 28 Hence, Sonuâs age 10 years ago = 28 â 10 = 18 years Thus, From I and From II, we can find the age of Sonu.Â
In a group of 5 boys and 4 girls, 5 students have to be selected. In how many ways it can be done so that only 2 boys are included.
Five articles out of which 3 are cups and rest are glasses have to be arranged on a shelf. Find the number of ways of arrangement in which all three cup...
6 students appear in an examination. In how many ways can the result be announced?
Find total number of ways in which the word âACCOMMODATEâ can be arranged.
How many 5-digit even numbers can be formed using the digits 0 to 9 if no digit is repeated?
- Eight books out of which 4 are part of a series and the remaining are standalone books are to be arranged on a shelf. Find the number of arrangements in wh...
- Seven balls out of which 4 are red and the rest are green are to be arranged in a row. Find the number of arrangements in which all four red balls are not ...
What will be the number of permutations of n different things, taken r at a time, where repeatition is allowed?
- There are 3 identical toys and 4 identical books. How many distinct arrangements are possible on a shelf such that all three toys do not appear together?
Find the no. of words formed by using all the letter of the word DISCOUNT, so that the vowels are never together?