# Math Help - Challenging Money Math Question

1. ## Challenging Money Math Question

How best can I approach the question below:

If Kwame had 3 cents more he would have twice as much as Ama. If he had 4 cents less, he would have the same amount.
How many cents does Kwame have?

a)4

b)7

c)11

d)14

e)none of the above

2. ## Re: Challenging Money Math Question

Originally Posted by KayPee
How best can I approach the question below:

If Kwame had 3 cents more he would have twice as much as Ama. If he had 4 cents less, he would have the same amount.
How many cents does Kwame have?

a)4

b)7

c)11

d)14

e)none of the above
Let $a$ be the amount that Ama has, now rewrite what you are told in terms of $a$.

CB

3. ## Re: Challenging Money Math Question

Let a be what Ama has and b be what Kwame has
b + 3 = 2a
b - 4= 2a

a = b + (3/2) = a

Substituting a into equation 2
b-4 = b + 3

I am stuck and the equation doesn’t sound ok

Where did I go wrong?

4. ## Re: Challenging Money Math Question

Originally Posted by KayPee
Let a be what Ama has and b be what Kwame has
b + 3 = 2a
b - 4= a
See the change in red above

CB

5. ## Re: Challenging Money Math Question

I solved it without using a (number thatAma has) in any equation. Here is how I did it (k being the number of Kwame's cents):

k + 3 = 2(k-4)
k + 3 = 2k - 8
k + 11 = 2k
11 = k

So Kwame has 11 cents. Using the simultaneous equations method you were using you can reach the same equation.

k + 3 = 2a
k - 4 = a

Using substituion and subbing the first into the second you can get to k + 3 = 2(k-4), as named earlier. Using elimination you can subtract the second from the first and get to 7 = a. Then sub the value for a into either equation to get k = 11.

6. ## Re: Challenging Money Math Question

Originally Posted by Ross137
k + 3 = 2a
k - 4 = a

Using substituion and subbing the first into the second you can get to k + 3 = 2(k-4), as named earlier. Using elimination you can subtract the second from the first and get to 7 = a. Then sub the value for a into either equation to get k = 11.
Simply subtract 2nd equation from 1st: k - k + 3 - (-4) = 2a - a
So 7 = a

7. ## Re: Challenging Money Math Question

Yep - that's what I meant by elimination