Question

Mr. Schwartz builds toy cars. He begins the week with a supply of 85 wheels, and uses 4 wheels for each car he builds. Mr. Schwartz plans to order more wheels once he has fewer than 40 wheels left. The inequality that can be used to find the number of cars, x, Mr. Schwartz builds before he places an order for more wheels is ? x < 40. Mr.Schwartz will need to order more wheels after building cars.

Answer 1

Answer with explanation:

Total number of Wheels that Mr. Schwartz has = 85 wheels

Number of wheels used by Mr.Schwartz for each car he builds = 4 Wheels

It is given that, Mr. Schwartz plans to order more wheels once he has fewer than 40 wheels left.

Number of cars made from 4 wheels =1

Let number of cars made before ordering for more wheels = x

⇒x= 4 y, where y is number of wheels used.

⇒Number of cars < 40

⇒ Total number of wheels =85

⇒ 4 y +40 <85

⇒4 y < 85 -40

⇒ 4 y< 45

$\Rightarrow 4 y< 45\\\\\Rightarrow y$

Also, x<40

So, after building  12 cars ,Mr.Schwartz will need to order more wheels for building cars.

Answer 2

Mr.Schwartz begins the week with = 85 wheels

Number of wheels used per car = 4

He orders more wheels when less than 40 wheels are left.

Given inequality is = x<40

The minimum number of wheels he can use before ordering more wheels= $85-40=45$

So, 45 minimum 45 wheels can be used before ordering more wheels.

4 wheels are used to make = 1 car

45 wheels are used to make = $\frac{45}{4}=11.25$ cars

If 12 cars are to be build then wheels required will be = $12\times4=48$

Beginning number of wheels = 85

Wheels used for making 12 cars = 48

Wheels left = $85-48=37$

But as mentioned, Mr. Schwartz orders wheels if they are less than 40, so after building 12 cars, 37 wheels will be left and he will order more.