Answer: 875
Step-by-step explanation:
The total number of fish bought was 320. And you know she bought two types of fish. The best way to solve this is guess and check. It would be the fastest. So she bought 7 times as many trigger-fish as parrot fish that means the number of trigger-fish bought was 7p. This means 320 = 7p +p. So all you do is take educated guesses for the number of parrot fish and check if it is right. So if she bought 50 parrot fish. 7(50) + 50 = 400. Close but a bit high. Lets keep guessing. 7(35) + 35 = 245. So now we know the answer is between 50 and 35. So lets try 40. 7(40) + 40 =320. That works so we know she bought 40 parrot fish and 280 trigger-fish.
For the first part:Every shirt she grabs, will cost her dollars, so if she grabs 3 shirts, then the cost of the shirts is:

With the same rationale, if she grabs 2 pairs of jeans, the cost of the jeans is:

So, her total is:

If you subtract 3 from the total, then the expression is:
For the second part:If she's paying 3 less for each shirt, then the cost of 3 shirts will become:

In the same fashion, for the two jeans:

So the expression for the total cost is:
For number three:The amounts are different because the cost of the total purchase is different than the cost of each element that makes up the total purchase.
For number four:If you're the owner, you want to give the smallest amount of discount (the one in part 1/a).
So you could clarify by saying there's 3 dollars of the TOTAL purchase's cost.
Answer:
son = 6 mother = 48
Step-by-step explanation:
Mother = m
son = s
m = 8s
m+6 = 9/2 * (s+6)
so
2(8s + 6) = 9(s +6)
16s + 12 = 9s + 54
16s - 9s = 54 - 12
7s = 42
s = 42/7 = 6 years old
so the mother is 8s = 8*6= 48 years old