q: The average amount with a group of seven numbers is Rs. 20. If the newly joined member has Rs. 50 with him, what was the average amount with the group before his joining the group?
Options:
(A) 22
(B) 27
(C) 15
(D) 77
(E) 16
a: Stream of consciousness: Total members in the group = 7
Average amount = Rs. 20
Total amount with them = 7 * 20 = Rs. 140
One number has Rs. 50. So, the amount with remaining 6 people = 140 - 50 = Rs. 90
The average amount with them = 90/6 = Rs. 15. The answer is (C).

question: The value of a machine depreciates at the rate of 10% every year. It was purchased 3 years ago. If its present value is Rs. 8748, its purchase price was :
Options:
(A) 12000
(B) 10000
(C) 15000
(D) 20000
(E) 25000
answer: Stream of consciousness: Purchase = 8748/(1-10/100^3) = 12000 The answer is (A).

q: The average of seven numbers is 26. The average of first three numbers is 14 and the average of last three numbers is 19. What is the middle number?
Options:
(A) 25
(B) 83
(C) 29
(D) 32
(E) 34
a: Stream of consciousness: The total of seven numbers = 7X26 = 182
The total of first 3 and last 3 numbers is = 3 X 14+3 X 19 = 99
So, the middle number is (182 - 99 ) = 83 The answer is (B).

question: Three grades of milk are 1 percent, 5 percent and 3 percent fat by volume. If x gallons of the 1 percent grade, y gallons of the 5 percent grade, and z gallons of the 3 percent grade are mixed to give x+y+z gallons of a 7 percent grade, what is x in terms of y and z?
Options:
(A) -1y - 2z
(B) (y +z) / 4
(C) 2y + 3z
(D) 3y + z
(E) 3y + 4.5z
answer: Stream of consciousness: Based on the given information, the following equation could be dervied: 1% * x + 5% * y + 3% * z = 7% * (x+y+z)
Then use algebra to figure out 6%*x = -2%*y - 4%*z. Thus, 3x = -1y - 2z. The answer is (A).

q: The average of seven numbers is 22. The average of first three numbers is 14 and the average of last three numbers is 19. What is the middle number?
Options:
(A) 27
(B) 55
(C) 31
(D) 34
(E) 35
a: Stream of consciousness: The total of seven numbers = 7X22 = 154
The total of first 3 and last 3 numbers is = 3 X 14+3 X 19 = 99
So, the middle number is (154 - 99 ) = 55 The answer is (B).

q: If 10 crates have 98 apples each and how many apples more is required in order to make 100 apples in each crate?
Options:
(A) 5
(B) 10
(C) 15
(D) 20
(E) 0
a:
Stream of consciousness: Each crate requires 2 apples and totally there are 10 crates so required apples = 10 * 2 = 20 The answer is (D).