Equations

Abby bought 3 sweaters that each cost the same amount and 1 skirt that cost $15. The items she bought cost a total of $90 before tax was added. Determine which equation could be used to find, x, the cost of each sweater.

• 3x - 15 = 90

• 3x + 15 = 90

• 15 - 3x = 90

• 15x + 3 = 90

Carlos paid an electrician x dollars per hour for a 4-hour job and $85 for parts. The total charge was $305. Which equation can be used to determine how much the electrician charged per hour?

• 4x – 85 = 305

• 4x + 85 = 305

• (85 + 4)x = 305

• (85 – 5)x = 305

Last week Tom earned $4.50 for every car he washed. He washed cars over the weekend and now has $63. Which equation shows x, the number of cars he washed?

• $63x = $4.50

• $4.50x = $63

• x ÷ $4.50 = $63

• $4.50 • $63 = x

Three-fourths of the students at Washington Junior High play sports. There  are 510 students who play sports.  Which equation would you use to find the number of students, x, at the school?

•  $\frac{3}{4}x\ =\ 510$  

•  $\frac{3}{4}\left(510\right)\ =\ x$  

•  $\frac{3}{4}\ =\ x$  

•  $\frac{3}{4\ }\ +\ x\ =\ 510$  

two fifths of the students at Durham Middle School play sports. There are 236 students who play instruments. Which equation would you use to find the number of students, s, at the school?

• $\frac{2}{5}\ s\ =236$

• $\frac{2}{5}\ 236\ =\ s$

• $\frac{2}{5\ }\ +\ s\ =\ 236$

• $s-\frac{2}{5}\ =\ 236$

Last week Hailey earned $7.50 for every car she washed. She washed cars over the weekend and now has $103. Which equation shows c, the number of cars she washed?

• 7.5 + c = 103

• 7.5 - c = 103

• 7.5c = 103

• 103+ 7.5 = c

Rogan paid an plumber x dollars per hour for a 6-hour job and $45 for parts. The total charge was $247. Which equation can be used to determine how much the electrician charged per hour?

• 45x + 6 = 247

• 6 (x + 45) = 247

• 6x - 45 = 247

• 6x + 45 = 247

Jacob bought 8 donuts that each cost the same amount and 1 soda that cost $4. The items he bought cost a total of $12 before tax was added. Determine which equation could be used to find, x, the cost of each donut.

• 4x + 8 = 12

• 12x = 8

• 8x + 4 = 12

• 8x - 4 = 12

Brady bought 3 games that each cost the same amount and 1 controller that cost $45. The items he bought cost a total of $180 before tax was added. Determine which equation could be used to find, x, the cost of each sweater.

• 3x + 45 = 180

• 3x - 45 = 180

• 45x + 3 = 180

• 3 (x - 45) = 180

Nathan paid a mechanic x dollars per hour for a 5-hour job and $120 for parts. The total charge was $350. Which equation can be used to determine how much the electrician charged per hour?

• 5x - 120 = 350

• 120x + 5 = 350

• 5x + 120 = 350

• 5 (x + 350 = 120