A united states presidential coin is made from an alloy of 4 metals-copper, zinc, manganese, and nickel- with weights in the ratio of 177:12:7:4 respectively. The coin weighs a total of 8 grams. What is the weight of the zinc in this coin?

0.32 grams

Step-by-step explanation:

ratio of weight of -copper, zinc, manganese, and nickel = 177:12:7:4

let the

weight of copper = 177x

weight of zinc = 12x

weight of manganese = 7x

weight of nickel = 4x

Total weight of this alloy in terms of x =  177x + 12x+ 7x + 4x = 300x

given weight of alloy = 8 grams

thus,

weight of this alloy in terms of x =given weight of alloy

300x = 8 grams

x = 8/300 grams =

weight of zinc = 12x = 12 * 8/300 grams = 96/300 grams = 0.32 grams

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!

6 spoons of sugar for every 21 cups of flour

step-by-step explanation: