The sum of two numbers is 100 and their difference is 20. What is the value of bigger number?

2 Answers
Apr 23, 2018

Value of bigger number is 60, smaller number is 40.

Explanation:

Let the bigger number be x.
x + (x - 20) = 100, as the difference is 20.
Solving for x we get 60, which is the bigger number.

Alternatively, you can draw a bar model to illustrate but i feel algebras faster.

Apr 23, 2018

60

Explanation:

"create 2 equations based on the given information"

"let x and y be the 2 numbers"

"with "x>y

rArrx+y=100to(1)larrcolor(blue)"sum of numbers"

rArrx-y=20to(2)larrcolor(blue)"difference of numbers"

"add (1)" and (2)" term by term"

(x+x)+(y-y)=(100+20)

rArr2x=120larrcolor(blue)"divide both sides by 2"

rArrx=60larrcolor(red)"the larger number"