word problem * yikes*

G

Guest

Guest
The sum of the digits of a two-digit number is 12.If 15 is added to the number, the result is 6 times the units digit. Find the number.

please help me I have a whole worksheet to do of those , and I really need some explainge :cry:
 
Make the two-digit number T and U. T is the tens unit and U is ones unit. So, T+U=12.

The rest I'm not exactly sure about.

I thought maybe 15+TU=6U

But, then I don't know how to solve it for sure... but that's what I would guess..
 
problems

This could be wrong.
I let x,y be the 2 digits.
So, x+y=12, and 10x+y+15=6y.
SO, i solved and i got 39.
Because 3+9=12, and 39+15 = 6*9.
 
Another approach:

1--Let the 2 digit number be 10A + B
2--Then, A + B = 12.
3--It follows that 10A + B + 15 = 6B or 10A + 15 = 5B
4--Multiplying A + B = 12 by 5 and adding to (3) yields
....10A + 15 = 5B
......5A - 60 = -5B or
5--15A = 45 making A = 3 and B = 9.
6--With the number being 39, we add 15 to get 54 which is 6x9.

7-
 
Always_Looking said:
The sum of the digits of a two-digit number is 12.If 15 is added to the number, the result is 6 times the units digit. Find the number.

please help me I have a whole worksheet to do of those , and I really need some explainge :cry:
Click to expand...

Let t = tens digit, and
let u = units digit

We know that the sum of the digits is 12, so
t + u = 12

The value of the two-digit number with t as the tens digit and u as the units digit is 10t + u.

If we add 15 to the number, then, we get 10t + u + 15, and we are told that this result is 6 times the unit digit, or 6u. So,
10t + u + 15 = 6u

You have a system of two equations in two variables:
t + u = 12
10t + u + 15 = 6u

Solve by your favorite method. Once you have values for t and u, you should be able to write the number for your answer (remember that the number is 10t + u).

I hope this helps you.
 
You must log in or register to reply here.
Top