If I have 4 hundred that are all worth 60% of my grade and one 0 that is worth 40% of my grade what's my grade? please, teachers of is my teacher is grading my stuff wrong?

answer:60%

Step-by-step explanation:

You get 60% and then you have 0% left because you got 0% and 100-40=60%

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.

answer: 8 years

step-by-step explanation:

the explanation is that in 8 years the child will be 20 and in 8 years the father will be 40 and 20 is half of 40.