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Question

A U.S. nickel is composed of 3.9 grams of copper and only 1.2 grams of nickel. How many kilograms of copper must be combined with 4 kilograms of nickel in the manufacture of nickel coins?

2. At a Certain college, the ratio of men to women is 6 to 5. if there are 2580 men, how many women are there?

Answer 1

1.
let:
X = mass of copper needed

take the ratio and proportion

3.9 g copper : 1.2 g nickel = X kg copper : 4 kg nickel

is the same as:

3.9 g copper / 1.2 g nickel = X kg copper / 4 kg nickel

so;

X kg copper = (3.9 g copper / 1.2 g nickel) x 4 kg nickel
= 3.9 g copper x 4 kg nickel / 1.2 g nickel
= 13 kg copper

therefore;
13 kgs of copper must be combined with 4 kgs of nickel in the manufacture of nickel coins...

2.
let:
X = no of women

take the ratio and proportion

6 men : 5 women = 2580 men : X women

is also the same as:

6 men / 5 women = 2580 men / X women

so;

X women = 2580 men x ( 5 women / 6 men )
= 2580 men x 5 women / 6 men
= 2150 women

therefore;
there are 2150 women, if there are 2580 men...


got it?!!!

Answer 2

3.9/x = 1.2/4000

Solve for x: x = 4000 * 3.9/1.2


6 Men / 5 Women = 2580 Men / X Women

X = 2580 * 5/6

Answer 3

x/4=3.9/1.2 so x= 13kg of copper

x/2580=5/6 x= 2580*5/6= 2150women

Answer 4

You have to put these values into ratios to solve them.

1) 3.9 / x = 1.2 / 4
x = 13 kg

2) 6 / 5 = 2580 / x
x = 2150.

Answer 5

1-
3.9/x = 1.2/4
x = 3.9/1.2 * 4 = 13kg of copper

2-
6/2580 = 5/x
x = 5*2580/6 = 2150 owmen

Answer 6

men : woman
6: 5
2580: x
2580 /6 = 430 *5 = 2150 woman

------------------------------------------
copper : nickel
3.9 : 1.2
x : 4kg
4/1.2 = 31/3
3.3333 *3.9 = 13 kg of copper