[Ques]: Out of 7 consonants and 4 vowels, how many words of 3 consonants and 2 vowels can be formed?
Options:
(A) 25200
(B) 2543
(C) 2344
(D) 233445
(E) 52757
*Ans*: (A)
--CoT--: Number of ways of selecting (3 consonants out of 7) and (2 vowels out of 4) = (7C3 x 4C2) = ( 7 x 6 x 5 x 4 x 3 ) 3 x 2 x 1 2 x 1 = 210. Number of groups, each having 3 consonants and 2 vowels = 210. Each group contains 5 letters. Number of ways of arranging 5 letters among themselves = 5! = 5 x 4 x 3 x 2 x 1 = 120. Required number of ways = (210 x 120) = 25200.

[Ques]: What approximate value should come in place of the question mark (?) in the following equation'?
3 35 of 157.85 + 39% of 1847 = ? 447.30
Options:
(A) 1200
(B) 1500
(C) 1600
(D) 1800
(E) 2100
*Ans*: (D)
--CoT--: ? 185 160 + 401000 1850 + 450
576 + 740 + 450 1760 1800

[Ques]: Some persons can do a piece of work in 24 days. Two times the number of these people will do half of that work in?
Options:
(A) 3
(B) 4
(C) 5
(D) 6
(E) 8
*Ans*: (D)
--CoT--: 24/ (2 * 2) = 6 days

[Ques]: P and Q can complete a work in 20 days and 12 days respectively. P alone started the work and Q joined him after 4 days till the completion of the work. How long did the work last?
Options:
(A) 5 days
(B) 9 days
(C) 30 days
(D) 20 days
(E) 10 days
*Ans*: (E)
--CoT--: Work done by P in 1 day = 1/20
Work done by Q in 1 day = 1/12
Work done by P in 4 days = 4 (1/20) = 1/5
Remaining work = 1 1/5 = 4/5
Work done by P and Q in 1 day = 1/20 + 1/12 = 8/60 = 2/15
Number of days P and Q take to complete the remaining work = (4/5) / (2/15) = 6
Total days = 4 + 6 = 10