[Question]: John found that the average of 15 numbers is 40. If 10 is added to each number then the mean of the numbers is?
[Options]: A)50, B)45, C)65, D)78, E)64
[Solution]: 
Let's think step by step. If 10 is added to each number, then the mean of the numbers also increases by 10. So the new mean would be 50. 
Answer: A

[Question]: If a / b = 3/4 and 8a + 5b = 22,then find the value of a.
[Options]: A)1/2, B)3/2, C)5/2, D)4/2, E)7/2
[Solution]: 
Let's think step by step. a / b = 3/4, then b = 4a / 3. So 8a + 5(4a / 3) = 22. This simplifies to 8a + 20a / 3 = 22, which means 44a / 3 = 22. So a is equal to 3/2. 
Answer: B

[Question]: A person is traveling at 20 km/hr and reached his destiny in 2.5 hr then find the distance?
[Options]: A)53 km, B)55 km, C)52 km, D)60 km, E)50 km
[Solution]: 
Let's think step by step. The distance that the person traveled would have been 20 km/hr * 2.5 hrs = 50 km. 
Answer: E

[Question]: How many keystrokes are needed to type the numbers from 1 to 500?
[Options]: A)1156, B)1392, C)1480, D)1562, E)1788
[Solution]: 
Let's think step by step. There are 9 one-digit numbers from 1 to 9. There are 90 two-digit numbers from 10 to 99. There are 401 three-digit numbers from 100 to 500. 9 + 90(2) + 401(3) = 1392. 
Answer: B

[Question]: {}
[Options]: {}
[Solution]: 
Let's think step by step.