Think about the inverse operations for multiplication and subtraction.

Arrange them in a linear equation and then work out the age.

Put the numbers in linear equation and then work out

Multiply by 5 both the sides.

Subtract 5/8 from both the sides.

Put them in an equation with one variable and then work out.

Convert the relation into a linear equation and then work out

Try to form an equation with one variable from the given conditions.

Try and think about the formula of perimeter of a rectangle.

Try and think about the property of an isosceles triangle to find the perimeter.