Math's Mate Pre-Algebra help?

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swimfree

New member
I have figured out every problem on my math's mate except for the last 2. Please help and if you don't like me asking for help on homework-don't say anything...because I need help and I have already tried by myself but obviously I can't figure it out. So,thanks in advance for any help!

Modeling clay is sold in cubes of two sizes. size A is a 10cm cube and costs$2.50. Size B is a 15cm cube and costs $7.50. Which size is a better buy?

One day Peter caught 100kg of fish. The total weight of the three largest fish was 35kg and of the three smallest fish was 25kg. How many fish did Peter catch all together?

Thanks:)
 
1) A is the better buy. Divide $2.50 by 10 because you want to see home much each ounce of clay costs. That comes out to $0.25. Divide $7.50 by 15 and you get $0.50. Therefore, the first one is cheaper
 
I agree with the person above me on the first, it is A

BELOW THE MANY STEPS THAT FOLLOW THIS TEXT IS A MUCH SIMPLER WAY TO TO THIS,
SIMPLY SCROLL DOWN TO THE NEXT ROW, THAT IS ALL CAPS.

I believe the answer to the last question to be 10 fish, my reasoning is explained below

1. I took the weight of the heavy fish and divided by 3, and got 11 2/3 KG a fish (approx) [35/3]
2. I took the weight of the light fish and divided by 3, and got 8 1/3 KG a fish (approx) [25/3]
3. If you take the total KG of light and heavy fish he bought you get a total of 60 KG [35+25 KG]
4. He caught a total of 100 KG therefore X number of fish make up the remaining 40 Kilos
5. So, i took those 40 kilos and divided by the avg, weight of a heavy fish, and got 3 fish
6. Then I took those 40 kilos and divided by the avg, weight of a light fish, and got 5 fish
7. Since the total weight of the 3 heaviest fish, and 3 lightest fish is given to us, it is safe to assume that it will be in the middle, (4 fish)
8. Add, 3 heavy, 3 light, and 4 in the middle, together you get 10


HERE IS ANOTHER WAY TO DO IT, THIS WAY IS ALSO EASIER;

you can cross multiply by aligning them as below so they correspond to one another and go the same make up the columns By that i mean one column (up and down) are fish, and another is Kilos, and that right from fish will be kilos, if this ins't followed cross multiplication will not work.

6 fish --------> 60 Kilos
X fish --------->100 Kilos

1. 6*100 = 600, fist, you need to multiply the two numbers that are given, and that are diagonal form one another, since you do not know what X is, you can only multiply six by 100,
2. After you have done that, you need to divide the product (600) by the reamining number, (diagonal from X) as below
600 /60 = 10 and you get your answer
 
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