Quantitative Aptitude - Arithmetic Ability Questions

The average temperature for Monday, Tuesday, Wednesday and Thursday was 48° . The average temperature for Tuesday, Wednesday, Thursday and Friday was 52°, If the temperature on Monday was 42°, then the temperature on Friday was (in degrees)

A boy spends Rs 20 to purchase toffees at Rs 1 each. Next day, he purchased some toffees for Rs 40 with a discount of 50 paise per toffee. What is the average price per toffee (in paise)?

Find the missing digit if it has 11 and 13 as factors?

P, Q and R are channels which discharge solutions A,B and C respectively in a tank. When the tank is empty and all the three channels are opened what is the proportion of the solution C in the tank after 3 minutes, if the channels P, Q and R can fill the tank from empty to full in 30 minutes and 20 minutes and 10 minutes respectively when they are opened one at a time.

In the following question, select the odd letter/letters from the given alternatives.

If the standard deviation of a population is 6.5, what would be the population variance?

A shopkeeper marks up his wares by 60% and offers 25% discount. What will be the selling price (in Rs) if the cost price is Rs 1600?

If P : Q : R = 6 : 7 : 8 and R : S = 3 : 5, then what is P : S?