The school choir is going on a trip. They plan on bringing 100 total bottles of water and juice with them. Each bottle of water costs $1 and each bottle of juice costs $2. If they spent $140 on drinks how many bottles of water did they buy? How many bottles of juice?

40 bottles of juice

60 bottles of water

Step-by-step explanation:

let w represent water, let j represent juice. set up a system of equations:

w+2j=140

w+j=100

isolate the w by itself on the bottom equation:

w=100-j

solve the top equation by substitution, substituting 100-j for w:

w+2j=140

100-j+2j=140

100+j=140

j=40

this means that they bought 40 bottles of juice.

to find the amount of bottles of water the bought, substitute 40 for j in either of the equations (i did it in the bottom one, because it's easier):

w=100-j

w=100-40

w=60

so, they bought 60 bottles of water.

y=3n + 1

step-by-step explanation:

this is wrong because it says the second number is one less and i added one instead

9 sandwiches per hour

step-by-step explanation:

when we have a rate, we want a 1 in the denominator

27/3 = 9

27 sandwiches/ 3 hours = 9 sandwiches/hour