Question

1) A party mi is made from pretzels that cost $2 lb. and cereal that costs $2.40 lb. If a total of 4 pounds is made and the cost for the mix is $2.15 a pound, how many pounds of each ingredient are used?

2) When the tens digit of a two digit number is added to three times the ones digit, the sum is 31. If the digits are added, the sum is 15. what is the original number?

Answer 1

Please Check it - I think I may have figured it out.
1) 1/2 lb cereal and .48 lb. of pretzels
2) 78

Am I right? :-)

Answer 2

#1 is obviously wrong, since your weights don't add up to the desired 4 lbs. If there are x lbs of pretzels,

2x + 2.4(4-x) = 2.15*4
x = 2.5
so, 2.5 lbs pretzels and 1.5 lbs cereal

#2 correct

Answer 3

Did you find these two problems on a cumulative review?