To solve this problem you must apply the proccedure shown below:
1. You must make a system of equations, as below:
2. Let's call:
x: the number of first class tickets bought.
y: the number of coach tickets bought.
3. Then, you have:
x+y=7 (First equation)
970x+370y=3790 (Second equation)
x=7-y
4. By substitution, you have:
970x+370y=3790
970(7-y)+370=3790
y=5
x=7-y
x=7-5
x=2
Therefore, the answer is:
- Number of first class tickets bought=2
- Number of coach tickets bought=5
You have to make an inequality:
1.2x + 6 ≤ 20
- 6 - 6 isolate x
1.2x ≤ 14
÷1.2 ÷1.2 isolate x
x ≤ 11.666
Since you can't buy 2/3 of a pack, she can only buy 11 pieces of gum.
Hope this helps!
For the order of operation use PEMDAS
Parenthesis
Exponent
Multiplication
Division
Addition
Subtraction
For memorizing the order you could say
Please
Excuse
My
Dear
Aunt
Sally
