Mario is x years old. In 7 years, he will be 19. Which equation can be used to determine Mario’s present age?(1 point) Answer truthfully, why are these answers true?

Question

Responses

x − 19 = 7
x minus 19 equals 7

x + 19 = 7
x plus 19 equals 7

x − 7 = 19
x minus 7 equals 19

x + 7 = 19
x plus 7 equals 19

Maria has to spend 512 hours to finish her community service program in a community health clinic. Last week, she was able to spend 334 hours. Which equation can be used to determine the number of hours, h, that Maria still needs to spend to complete her service program?(1 point)
Responses

h + 334 = 512
h plus 3 and three-fourths equals 5 and one-half

h − 512 = 334
h minus 5 and one-half equals 3 and three-fourths

h − 334 = 512
h minus 3 and three-fourths equals 5 and one-half

h + 512 = 334
h plus 5 and one-half equals 3 and three-fourths

You have p dollars in your piggy bank. You spent $13.32 to buy a toy, leaving you with $25.70. Which equation should be used to determine the amount of money you had in your piggy bank before buying the toy? How much money was in the piggy bank?(1 point)
Responses

p − 25.70 = 13.32; there was $12.38 in the piggy bank.
p minus 25.70 equals 13.32 ; there was $12.38 in the piggy bank.

p + 13.32 = 25.70; there was $12.38 in the piggy bank.
p plus 13.32 equals 25.70 ; there was $12.38 in the piggy bank.

p + 25.70 = 13.32; there was –$12.38 in the piggy bank.
p plus 25.70 equals 13.32 ; there was –$12.38 in the piggy bank.

p − 13.32 = 25.70; ; there was $39.02 in the piggy bank.
p minus 13.32 equals 25.70 ; ; there was $39.02 in the piggy bank.

Krista and Alexa played balloon darts in a school fair. Krista popped 5 balloons and Alexa popped n balloons. Together, they popped a total of 13 balloons. Which equation can be used to determine the number of balloons Alexa popped? How many balloons did she pop?(1 point)
Responses

n − 5 = 13; Alexa popped 18 balloons.
n minus 5 equals 13 ; Alexa popped 18 balloons.

n − 13 = 5; Alexa popped 18 balloons.
n minus 13 equals 5 ; Alexa popped 18 balloons.

n + 5 = 13; Alexa popped 8 balloons.
n plus 5 equals 13 ; Alexa popped 8 balloons.

n + 13 = 5; Alexa popped 8 balloons.
n plus 13 equals 5 ; Alexa popped 8 balloons.

Due to excessive heat, the water level in a dam decreased by 8.8 meters last month. Now, the water level is 95.3 meters. Which equation represents the water level, w, of the dam last month? What was the water level last month?(1 point)
Responses

w + 8.8 = 95.3; the water level of the dam last month was 86.5 meters.
w plus 8.8 equals 95.3 ; the water level of the dam last month was 86.5 meters.

w + 95.3 = 8.8; the water level of the dam last month was 104.1 meters.
w plus 95.3 equals 8.8 ; the water level of the dam last month was 104.1 meters.

w − 95.3 = 8.8; the water level of the dam last month was 86.5 meters.
w minus 95.3 equals 8.8 ; the water level of the dam last month was 86.5 meters.

w − 8.8 = 95.3; the water level of the dam last month was 104.1 meters.
w minus 8.8 equals 95.3 ; the water level of the dam last month was 104.1 meters.

Answer 1

1. The equation that can be used to determine Mario's present age is x + 7 = 19. Mario's age in 7 years will be 19, so his present age can be determined by subtracting 7 from 19.
2. The equation that can be used to determine the number of hours Maria still needs to spend to complete her service program is h = 512 - 334. Maria needs to spend a total of 512 hours and she has already spent 334 hours, so the remaining hours can be found by subtracting 334 from 512.
3. The equation that should be used to determine the amount of money in the piggy bank before buying the toy is p + 13.32 = 25.70. The amount of money in the piggy bank before buying the toy can be determined by adding the price of the toy ($13.32) to the amount of money left after the purchase ($25.70).
4. The equation that can be used to determine the number of balloons Alexa popped is n + 5 = 13. The total number of popped balloons is the sum of Krista's popped balloons (5) and Alexa's popped balloons (n), which equals 13.
5. The equation that represents the water level of the dam last month is w = 95.3 - 8.8. The current water level (95.3) is the result of a decrease in water level by 8.8 meters, so the water level last month can be found by subtracting 8.8 from 95.3.