SOLUTION: How old is the younger of two siblings if the sum of their ages is 18 and the difference is 10?

Question 689894: How old is the younger of two siblings if the sum of their ages is 18 and the difference is 10?
Answer by MathLover1(20850) (Show Source): You can put this solution on YOUR website!

let's the younger of two siblings be (the older of two siblings) and (the younger of two siblings)

if the of their ages is , we have
.........eq. 1

and if the difference is , we have
.........eq. 2

solve the system:

.........eq. 1
.........eq. 2
________________________

.........eq. 1.....solve for

so, the younger of two siblings is years old

..........eq. 1a..........plug it in eq. 2

.........eq. 2

now go to eq. 1a and find

..........eq. 1a

so, the younger of two siblings is years old

RELATED QUESTIONS
maria is 3 years older than her brother, luis. luis is 2 years older than their younger... (answered by Fombitz)

Jaya is 10 yrs younger than Sid. If you increase both of their ages by 20 %, the... (answered by Maths68)

Esther is 18 years younger than her mother. If the sum of their ages 2 years ago was... (answered by josmiceli)

Tom is five years older than his sister Melissa, and three times the sum of the ages of... (answered by ankor@dixie-net.com)

Ruby is younger than Janeth. The sum of their ages is 31. The difference between their... (answered by Fombitz)

ELi is younger than Lily. The sum of their ages is 31. The difference between their ages... (answered by Fombitz)

Mary is younger than her husband, but their ages contain the same two digits. The sum of... (answered by ankor@dixie-net.com)

Bob is twice as old as Chuck and Susie is 10 years younger than Bob is the sum of their... (answered by ewatrrr,josmiceli)

Nadine is two years younger than Mark. The sum of their ages is 28. How old is... (answered by ikleyn)