I need to solve this problem

Step-by-step explanation:

First add 45 and 78 to find the total weight in grams.

45 + 78 = 123

Then find the weights that will work 1 100, 2 10, 3 1,

-7/8

step-by-step explanation:

instead of subtracting you add the -6/8 and -1/8

54 kilometers per hour

step-by-step explanation:

according to rules:

1 km = 1000 meter

which means that 1 meter = 1/1000 km

1 hour = 3600 second [ as 1 hour = 60 min = 60 *60 seconds ]

which means that 1 second = 1/3600 hour

therefore, 1 kilometer/hour =

thus to convert 15 meter per second to kilometer per hour, we multiply 15 to 3.6 kilometer/hour.

15 meter/second=   which is the required answer.