Ametallurgist has one alloy containing 49%49% copper and another containing 62%62% copper. how many pounds of each alloy must he use to make 5151 pounds of a third alloy containing 56%56% copper? (round to two decimal places if necessary.)

2377.38 pounds of the first alloy

2773.62 pounds of the second alloy

Step-by-step explanation:

First, let Alloy1 represent the alloy with 49% copper, Alloy2 the alloy with 62%, and Alloy3 the alloy with 56%.

The third alloy is made from a mixture of the first two, so:

MassAlloy1 + MassAlloy2 = MassAlloy3        

MassAlloy1 + MassAlloy2 = 5151 lb         eq.1

MassCopper1 = MassAlloy1 * 0.49        eq.2

MassCopper2 = MassAlloy2 * 0.62       eq.3

MassCopper3 = MassAlloy3 * 0.56        eq.4

The problem tells us that MassAlloy3 = 5151 lb, thus the copper mass in the third alloy is:

MassCopper3 =  5151 lb * 0.56 = 2884.56 lb

MassCopper1 + MassCopper2 = MassCopper3

MassCopper1 + MassCopper2 = 2884.56 lb         eq.5

MassAlloy1 * 0.49 + MassAlloy2 * 0.62 = 2884. 56 lb     eq.6

Eq. 1 and Eq. 6 give us a system of two equations and two unknowns, so we can solve it:

MassAlloy1 + MassAlloy2 = 5151 lb  

MA1 = 5151 - MA2

MassAlloy1 * 0.49 + MassAlloy2 * 0.62 = 2884. 56 lb

(5151-MA2) * 0.49 + MA2 * 0.62 = 2884.56

2523.99 - 0.49MA2 + 0.62MA2 = 2884.56

0.13MA2 = 360.57

MA2 = 2773.62

MassAlloy1 + MassAlloy2 = 5151 lb

MassAlloy1 + 2773.62 lb = 5151 lb

MassAlloy1 =2377.38 lb

3

step-by-step explanation:

in standard form:

a= dictionaries

b= maps

you have to buy 3 dictionaries, so put a 3 next to the a (dictionaries) so that you can multiply them by each other.

a3+b= 60 (the amount of money you have)

we already know the cost of a=15 so replace a with $15

($15 x 3)+b=60

multiply 15 and 3 to get $45 and replace it with $45

45+b=60

and then replace b with 15 to get the total:

45+15=60

that means you have $15 left after buying 3 dictionaries.

15 divided by the cost of a map ($5) equals 3.

so you can buy 3 maps.

sorry if it was confusing!

n=9

step-by-step explanation:

7 times a number = 7n

decreased by 13 = 7n-13

same as is =

5 times the number = 5n

increased by 5 = 5n+5

7n-13 = 5n+5

2n=18

n=9