3.9 Continued….Word Problems Involving Proportions How do you know when to use proportions? When you see a comparison of units

How to tackle word problems Set up a table Set up a proportion Cross multiply Set products equal Solve for x Put units on answer units Fill in the blank

1. ) A car travels 150 km on 12 l of gasoline 1.) A car travels 150 km on 12 l of gasoline. How many liters of gasoline are needed to travel 500 km? Liters of Gasoline 12 x KM 150 500 12(500) = 150 (x) 6000 =150x 40 Liters of Gasoline =x

2. ) A watch loses 2 minutes every 15 hours 2.) A watch loses 2 minutes every 15 hours. How much time will it loose in 2 hours? minutes 2 x hours 15 15(x) = 2(2) 15x =4 X = of a minute

3. ) On a certain map, 2 inches represents 5 miles 3.) On a certain map, 2 inches represents 5 miles. 9 inches represent how many miles? inches 2 9 miles 5 x 2(X) = 5(9) 2x =45 X = 45/2 or 22.5 miles

4 64 5 x 4x = 320 X = 80 shovels of gravel 4.) 4 shovels of sand are used for every 5 shovels of gravel in making concrete. How much gravel is needed for 64 shovels of sand? Shovels of sand 4 64 Shovels of gravel 5 x 4(x) = 5 (64) 4x = 320 X = 80 shovels of gravel

Assignment Page 150 ( 26-38) even you do not have to write down the entire word problem but you do need the table, the proportion and work