Question

Two numbers have a sum of 7. When the smaller number is subtracted from twice the larger number, the result is 20. Which is the following is the larger number.
11
9
15
12
Which is it?

Answer 1

Answer:

9

Step-by-step explanation:

according to the condition it is possible to make up a system of two equations (if to suppose 'l' - the larger number and the 's' - is the smaller one):

1. 'two numbers have a sum of 7' means s+l=7;

2. 'When the smaller number is subtracted from twice the larger number, the result is 20' means 2*l-s=20.

3. the system of two equations is:

$\left \{ {{s+l=7} \atop {2l-s=20}} \right. \ => \left \{ {{s=-2} \atop {l=9}} \right.$

4. the larger number is 9.