Quantitative Aptitude - Arithmetic Ability Questions

In the given series, how many 8s are there that are not divisible by the number to its left but completely divisible by the number to its right.

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Working together, pipes A and B can fill an empty tank in 10 hours. They worked together for 4 hours and then B stopped and A continued filling the tank till it was full. It took a total of 13 hours to fill the tank. How long would it take A to fill the empty tank alone?

An angle is four times its complementary angle. What is the measure of the angle?

Which of the following quadratic equations has equal roots?

If 1/4th of the wall is painted blue, 1/2 is painted yellow and remaining 3 m is painted white, what is the length of the wall?

Given: 5x -3(2x-7) > 3x - 1 < 7 + 4x; then x can take which of the following values?

If 9x - 6(3 - x) = 12, then the value of x is

When a number is increased by 42, it becomes 121% of itself. What is the number?