Manuel traveled 31 hours nonstop to Mexico, a total of 2,300 miles. He took a train part of the way, which averaged 80 mph, and then took a bus the remaining distance, which averaged 60 mph. How long was Manuel on the train?

he was on the train for 22 hours.

Step-by-step explanation:

Let t represent the time that Manuel spent on the train to Mexico.

Manuel traveled 31 hours nonstop to Mexico. This means that the time he spent on the bus is (31 - t) hours

Distance = speed × time

He took a train part of the way, which averaged 80 mph. This means that the distance he traveled on the train is 80t

Then, he took a bus the remaining distance, which averaged 60 mph. This means that the distance he traveled on the train is 60(31 - t)

Since the total distance covered is 2300 miles, it means that

80t + 60(31 - t) = 2300

80t + 1860 - 60t = 2300

80t - 60t = 2300 - 1860

20t = 440

t = 440/20

t = 22

solution:

→c= a b , that is product of a and b is possible only when when a is m × n matrix and b is n × p matrix.

that is, number of columns of a= number of rows of b.

so, size of matrix , c= a b is , if a = (m × n)matrix

b= (n × p)matrix

then a b = [ (m × n)matrix] ×[   (n × p)matrix ]

→→c= a b= [m × p ] matrix

→→size of product a b will be equal to = number of rows of a × number of columns of b

the correct option is b

step-by-step explanation: