A car traveled from San Diego to San Francisco at an average speed of 66 miles per hour. If the journey back took twice as long, what was the average speed of the trip?
Options:
(A) 24.
(B) 32.
(C) 36.
(D) 42.
(E) 44.

Let the time taken be = x
One way distance = 66x
Total distance traveled = 2 * 66x = 132x
Total time taken = x + 2x = 3x
Average speed = 132x/3x = 44 So the answer is: (E).

Fill in the blank with the correct number in this number series: 1, 20, 7, 16, __, 12, 19, ?
Options:
(A) 14
(B) 12
(C) 13
(D) 15
(E) 11

This is a simple alternating subtraction and addition series; The first series begins with 1 and adds 6; the second begins with 20 and subtracts 4, and so on. So the answer is: (C).

If x is an even integer and y is an odd integer, which of the following is an even integer?
Options:
(A) x+y
(B) x+2y
(C) 3x+y
(D) x+y^2
(E) x+y+2

Plug in an even integer for x; in this case 2
Plug in an odd integer for y; in this case 1
2+1 = 3 Odd
2+(2*1) = 4 Even
(3*2)+1 = 6 + 1 = 7 Odd
2+(1^2) = 2 + 1 = 3 Odd
2+1+2 = 5 Odd So the answer is: (B).

What is the are of an equilateral triangle of side 16 cm?
Options:
(A) 645
(B) 649
(C) 644
(D) 643
(E) 642
Area of an equilateral triangle = 3/4 S2
If S = 16, Area of triangle = 3/4 * 16 * 16 = 643 cm2; So the answer is: (D).