A car travels at 20 meters per second. what is its rate per hour ?

A) 72 kilometers per hour
B) 5.6 kilometers per hour
C) 1.2 kilometers per hour
D) 56 kilometers per hour

A) 72 kilometers per hour

Step-by-step explanation:

It goes 72 kilometers per hour because to there are 60 seconds in a minute and so you have to multiply 20 * 60 so, 1200 meters per minute and there are 60 minutes in a hour so you multiply 1200 * 60 so, that is 72,000 meters per hour. and since there are 1,000 meters in one kilometer you divide 72,000  so 72 kilometers per hour.

50-38=12

step-by-step explanation:

the largest number of the four options is 1.8 x 10-2

you have it in scientific notation.

1.80 x 10-6   = 0.00000180

1.80 x 10-4   = 0.000180 (bigger, or "less small", than the former one)

so

1.8 x 10-2       = 0.0180. as you see. the "less small", or the biggest one of them all.

as you have negative exponent, it means you are dividing 1.8 by 100 (i.e. moving the dot towards left, two times).

if you had positive exponent for the scientific notation, power of tenths, you would be multiplying times 100 (moving the dot towards right) as below:

1.8 x (10)2 = 180

so. if you have negative exponent in scientific notation, move the dot toward left. if it is positive, toward right as many times the exponent tells you.