Answer:
11
Step-by-step explanation:
First, write an equation to represent the situation.
34 = 2a + 12
This equation works because your combined age is half of 68, so 34. If your age is a, then yours sister's age is a + 12. if you add your age to your sister's, you get 2a + 12.
Now just solve for a.
34 = 2a + 12
First, subtract 12 from both sides.
22 = 2a
Then divide both sides by 2.
11 = a
So you are 11 years old. If you need to check your work, your age (11) plus your sister's age (11 + 12, which is 23) is 34, which is half of your grandfather's age.
Answer:
3
Step-by-step explanation:
Answer:
51 DVDs
Step-by-step explanation:
Let the number of DVDs and CDs sold be x each.
<u>Initial</u>
Number of DVDs= 86
Number of CDs= 52
<u>After selling</u>
Number of DVDs= 86 -x
Number of CDs= 52 -x
Given that there are 3 times as many DVDs than CDs left,
86 -x= 3(52 -x)
<em>Expand:</em>
86 -x= 156 -3x
<em>Bring x terms to 1 side, constant to the other:</em>
3x -x= 156 -86
<em>Simplify:</em>
2x= 70
<em>Divide both sides by 2:</em>
x= 35
Amount of DVDs left
= 86 -x
= 86 -35
= 51
