Problems in linear equations St. Angela ( Group 5)

1st problem

1st problem Paula is now 18 years old and her colleague Monica is now 14 years old. How many years ago was Paula twice as old as Monica?

Chart Past Present Paula 18-x 18 Monica 14-x 14

Solution (18-x) - 2(14-x) 18-x = 28-2x

answer X = 10

2nd Problem

2nd problem A triangular Pyramid with a square base has a height equal to two times the side of it’s base. Find the dimension of the Pyramid if the volume is 100 cu. cm

Solution Height = 2 Side of the base = x NOTE = Volume of the pyramid = 1/3 ( Area of the base) x height 100 = 1/3 (x^2)(2x) 100 = 2/3 (x^3) X = cube root of 150 Height = 2x 2( cube root of 150)

Height = 2 cube root of 150 Side of base = cube root of 150 Answer Height = 2 cube root of 150 Side of base = cube root of 150

3rd problem

3rd problem JJ is three times older as Jan-Jan. Three years ago, JJ was four times as old as Jan-Jan. the sum of there age is?

CHART Past Present JJ 3x-3 3x Jan-Jan X-3 x

solution 3x-3 = 4(x-3) 3x-3 = 4x-12 X-12 = 3 x = Jan- Jan’s age 3x = 27 ( JJ’s age )

answers Sum of ages = 9 + 27 = 36