Ques: The average of ten numbers is 210. The average of first five numbers is 40 and the average of last four numbers is 200. What is the middle number?
Options:
(A) A) 200
(B) B) 2000
(C) C) 800
(D) D) 2100
(E) E) 1100
Ans: (E)
CoT: The total of ten numbers = 10X210 = 2100
The total of first 5 and last 4 numbers is = 5 X 40+4 X 200 = 1000
So, the middle number is (2100 - 1000 ) = 1100

Ques: The volume of a certain substance is always directly proportional to its weight. If 48 cubic inches of the substance weigh 112 ounces, what is the volume, in cubic inches, of 53 ounces of this substance?
Options:
(A) 27
(B) 36
(C) 42
(D) 22
(E) 147
Ans: (D)
CoT: 112 ounces of a substance has a volume of 48 cubic inches
53 ounces of a substance has a volume of (48/112)*53 = 22 cubic inches

Ques: A no. when divided by the sum of 555 and 445 gives 2times their difference as quotient & 30 as remainder. Find the no. is?
Options:
(A) 234354
(B) 243435
(C) 243445
(D) 245667
(E) 220030
Ans: (E)
CoT: (555 + 445) * 2 * 110 + 30 = 220000 + 30 = 220030

Ques: The average of first four prime numbers greater than 10 is?
Options:
(A) 10
(B) 20
(C) 15
(D) 40
(E) 50
Ans: (C)
CoT: 11 + 13 + 17 + 19 = 60/4 = 15