In which two operations, there will be no affect on answers even by changing the order of numbers.

Think about the total number of bottles and then multiply that by the cost of each bottle.

Try by putting the values of a which is given in the options below.

First find, the total money he would earned in one day and then find the total money he would earned in 30 days.

Think about the difference between any two consecutive numbers.

With which property of whole numbers, we can rearrange numbers under addition.

Think any number, which gave you the same number as an answer after addition.

Think of distributive property of whole numbers.

Use distributive property

In which property, can we rearrange values?