Answer:
speed = distance/time
Step-by-step explanation:
The faster a sound wave travels, the more distance it will cover in the same period of time. If a sound wave were observed to travel a distance of 700 meters in 2 seconds, then the speed of the wave would be 350 m/s.
X and y are the numbers
y>x
sum (addition) of twice a number (2x) and larger number (y) is (=) 145
2x+y=145
difference between them is 55 (y is bigger so it would be x is subtracted from y)
y-x=55
so the equations are
2x+y=145 and
y-x=55
we could add x to both sides in the 2nd equation to obtain
y=x+55, but that doesn't really represent that the difference is 55, though they are the same euation
so I would say C and D only
Answer: The answer is D
Step-by-step explanation: 12x means 12 times x, which means her age is 12 times her brother's age.
210 because 7th graders washed 12 cars, 8th graders washed 14 cars, 6th graders washed 16 cars. Added all together and multiplied by 5, it equals 210
