If "–" stands for division, "+" stands for multiplication, "÷" stands for subtraction and "×" stands for addition, which of the following equations is correct?

Which two numbers should be interchanged to make the following equation correct?
7 – 8 ÷ 4 + 5 × 3 = 8 × 3 + 6 ÷ 2 – 3

Select the set in which the number are related in the same way as are the number of the following set.
( 11, 16, 20)

Adam who is 20 years old is 4 times as old as Mary. What will be Mary’s age when Adam is twice as old as her?

If ‘×’ denotes ‘ – ‘. ‘+’ denotes ‘×’ . ‘÷’ denotes ‘+’ and ‘ – ‘ denotes ‘÷’. Then Find out the value of the following equations.
175 – 25 ÷ 5 + 20 × 3 + 10=?

If “+” denotes ‘ – ‘ , ‘ – ‘ denotes ‘× ‘, ‘×’ denotes ‘÷’  and ‘÷’ denotes ‘+’, then what is the value of
15 – 5 +15 ÷ 45 × 15

Mrs. and Mr. Gopal have 3 daughters. Each daughter also has a brother. So how many members are there in this family?

Rahul’s age is three times the age of Sumit. If Rahul is 15 years old presently, determine the age (in years) of Sumit after 12 years.