A square has an area of 49in^2. If the same amount is added to the length and removed from the width, the resulting rectangle has an area of 45in^2. Find the dimensions of the rectangle Round your answer to the nearest tenth, when appropriate

50 grams of 45% alloy and 50 grams of tin alloy

Step-by-step explanation:

Those are the two equations:

x+y=100

the sum of the weight of both alloys is 100 g

0.5x+0.45y=0.25*100

the sum of the weights of tin has to be 25% of 100g, which is actually 25 g

0.5x+0.45y=25

So we have:

x+y=100

0.5x+0.45y=25

x=10-y

0.5x+0.45y=25

We substitute:

0.5(10-y)+0.45y=25

We calculate:

5-0.5y+0.45y=25

-0.5y+0.45y=20

0.4y=20

4y=200

y=50

So he needs 50 grams of 45% alloy and 100-50=50 grams of tin alloy as well