Question

In 5 years, Dad will be three times as old as his daughter Jill will be then. If the sum of their present ages is 50, how old are they now?

If x + 5 is Jill's age five years from now, which of the following equations could be used to solve the problem?


3x + 5 = 55 - x
3x + 15 = 55 - x
3x + 15 = 45 - x

Answer 1

x+y=50
(x+5)3=y=5 ---> 3x+15=y+5 ---> 3x+10=y

substitute,
x+(3x+10)=50
4x+10=50
4x=40
x=10

this is the way I would do it.

Answer 2

I think it is B.

Answer 3

thank you

Answer 4

Anytime!

Answer 5

what about this one?

The length of a rectangle is 2 more than twice the width. Find the dimensions of the rectangle if the perimeter is 76.

If x represents the width of the rectangle, then which expression represents the perimeter?


2x + 2
4x + 4
6x + 4

Answer 6

l-2=2w
lw=76

can you solve this system?

Answer 7

l -- lenght
w -- width

Answer 8

sorry no

Answer 9

l-2=2w ----> l=2w + 2
lw=76

substitute,
w(2w + 2)=76
2w^2+2w-76=0

use Completing the square, factoring, or quadratic formula to solve this.

can you?

Answer 10

2w^2+2w-76=0
divide the entire equation by 2
w^2+w-32=0
can you solve this?