Tim has completed five math problems and 13 minutes if he continues at the same rate how long will it take him to finish 20 problems

52 minutes

Step-by-step explanation:

it takes him 13 minutes to complete 5 so if he wants  to do 20 problems  do 20 divided by 5 (4) then do 13 times 4=52

the sum of the lengths of any two sides of a triangle is greater than the length of the third side. if you take the three sides of a triangle and add them in pairs, the sum is greater than (not equal to) the third side. if that is not true, then it is not possible to construct a triangle with the given side lengths.

step-by-step explanation:

c.

step-by-step explanation:

because first you have to add the 4x, 9x, and the 7x together and you get 20x and then you add the last numbers up and you get 5and then you put the subtraction sign in there and that's how you get the answer.