Question

The average of 5 numbers is 12. The average ofthree of those numbers is 10. What is the average ofthe remaining two numbers?

Answer 1

`10=(x+y+z)/(3)`
`30=x+y+z`
`12=((x+y+z)+a+b)/(5)`
`12\cdot5=30+a+b`
`60=30+a+b`
`30=a+b`
`15=(a+b)/(2)`