# 2 numbers are first added together and then multiplied together. The numbers added together = 18 and the numbers multiplied together = 45. What are the 2 numbers?

Question asked by: knowitall

**Comment or provide your answer to this question**

### Comments and other answers:

The two numbers are 15 & 3... Doesn't matter which order you choose to put them in, it'll still work.
Here's how I came up with it using algebra:
Firstly note:
a x b = 45
therefore: b = 45/a (equation 1)
Second, note that:
a + b = 18 (equation 2)
now we can substitute equation 2 into equation 1:
a + (45/a) = 18
rearraning:
a - 18 + (45/a) = 0
multiply by factor of a:
a^2 - 18a + 45 = 0 (equation 3)
Thirdly, note that equation 3 is a solveable quadratic equation with real solutions of a=3 and a=15.
Substituting either solution back into equation 1 gives:
a=3 and b=15
or
a=15 and b=3
QED.

By: Sacha001

By: Sacha001

*Date of comment: Thu, Jul 15th 2010*
Yeah, I think the person asking the question wants to see the algebraic arithmatic actually working out the answer!

By: sb70520

By: sb70520

*Date of comment: Sun, Jun 13th 2010*
First no is 15 and secon no is 3
when you will add 15+3=18
when you will multiply 15*3=45

By: susanta

By: susanta

*Date of comment: Wed, Jul 22nd 2009***Ask a New Question**

Find out more about Maths

Maths Questions and Answers

maths exam questions Questions and Answers

Next question: A dice is thrown 80 times. it lands on a six 12 times. What is the probability of throwing a six?

**Become a Member! It's Free >>>**

**Share on Facebook:**
**On Twitter:**
Tweet this!
**Question Keywords**

numbers multiplied added **More Questions:**

Consecutive Numbers

Whats The Answer To This Sequence:3,3,6,18,72 And Can You Tell Me How You Got It?

In A A SUDOKU Game Of 9X9 How Many Possibilities Of Combinations Are There ?

Probability Question?

Equation