Question 702005
Bill Phipps is 6 times as old as his 5-year old niece


So Bill is 6*5 = 30 years old


In x years, he will be 30+x years old


In x years, she will be 5+x years old


If you want to know when he will be twice her age, simply say


30+x = 2(5+x)


Then solve for x


30+x=2(5+x)


30+x=10+2x


x=10+2x-30


x-2x=10-30


-x=10-30


-x=-20


x=(-20)/(-1)


x=20


So it will take 20 years for him to be twice as old as her.


Notice how adding 20 years to 30 makes him now 50. Adding the same 20 years to 5 makes her now 25. Finally, notice that 50 is double of 25. So the answer checks.