1. Section 7.4: Applications with Linear Systems

2. A hardware store orders a shipment of two types of hammers for $168. One type of hammer costs $3; the other type of hammer costs $5. If the store ordered 40 hammers in all, how many of each type were ordered? x=$3 hammer y=$5 hammer 1 st equation is the money 2 nd equation is always x+y=how many There are 24 - $5 hammers and 16 - $3 hammers.

3. 2. With a given head wind, a certain airplane can travel 3600 km in 9 h. Flying in the opposite direction with the same wind blowing, the airplane can fly the same distance in 1 h less time. Find the speed of the airplane in still air and the wind speed. Time XRate =Distance Tailwind Headwind Faster Slower 8 9 (x+y) (x-y)3600 Here is a trick instead of distributing X= plane speed Y= wind speed But what does this mean? The plane speed is 425 km/hr The wind speed is 25 km/hr