Work and Mixture Problems

How many ounces of a 30% acid solution should be mixed with 40 ounces of a 2% acid solution to make a 5% acid solution?

A 40 lb. bag of gravel that was 80% small stones by weight was mixed with another bag that was 60% small stones by weight to produce a new mixture that was 67% small stones by weight.

What was the weight of the other bag? Round to the nearest tenth of a lb.

Which equation could help you find how many ounces of 30% acid solution should be mixed with 50 ounces of 2% acid solution to make 3% acid solution?

What amount of 20% salt solution should be mixed with some 8% salt solution to make 500 ml of a 15% salt solution?

One drilling machine can complete a tunnel in 4 years, and another drilling machine can complete the same tunnel in 3 years. If they worked together how long would it take to complete the tunnel?

The Georgia Demolition Company wants to build a brick wall to hide the wrecked cars from public view. One brick layer can build this wall in 5 days, and another brick layer can build the same wall in 4 days. If they worked together how many days would it take to build the wall?

Working together, two painting restorers were able to restore a masterpiece in 20 weeks. Working alone it would have taken one of the restorers 24 weeks. How long would it have taken if the other restorer worked alone?