Tonya and Mario are asked to use a pan balance to find the mass of the same rock. Tonya finds the rock's mass to be 680 grams. Mario finds the rock's mass to be 672 grams. Which is the best explanation for the difference in their measurements? A. Either Mario or Tonya measured the mass of the rock incorrectly on the pan balance.

B. The rock was cold when Tonya measured its mass and hot when Mario measured in mass.

C. The rock changed in size between the time Tonya measured it and the time Mario measured it.

D. The rock broke before Mario measured it. So the mass of the two pieces together was less than when Tonya measured it. PLEAS HELPPP

answer: 2/4

step-by-step explanation:

2 & 7

step-by-step explanation:

he climbs 300 ft/hr at a constant rate. the peak is at 1,500 ft.

when going up, he reaches 600 ft in 2 hours. remember, that he is going in a constant rate. divide 600 with 300:

600/300 = 2

assuming that he takes the same route back (meaning that it's a 1500 ft route back, you can solve.

note also that you are solving when he gets back to 600 ft after he reaches the peak.

first, find the amount of hours it takes to get up the peak. divide the total amount (1500), with the ft/her (300) to get the amount of hours (x):

1500/300 = x

x = 5

it takes jamie 5 hours to get up. now, he is returning down, and reaches 600 (his current destination). remember that he climbs at a constant 300 ft/hr. divide 600 with 300:

600/300 = x

x = 2

now add the two numbers together.

x = 5 + 2 = 7

jamie takes 7 hours to go up the mountain and reach his current position when descending.

(total amount/constant rate) = (time).

remember that it is a constant rate, so in total, when he gets back down the mountain, it will take the same amount of time as when he goes up. the total amount for the round trip is: 5 + 5 = 10.

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