When Mariana does 19 push-ups and 6 sit-ups, it takes a total of 75 seconds. In comparison, she needs 72 seconds to do 18 push-ups and 6 sit-ups. How long does it take Mariana to do
each kind of exercise?
HELP

 It takes 3 seconds to do one of both i think

Step-by-step explanation:

19 and 6 was 75 and 18 and 6 was 72 which means 1 push up is 3 seconds multiply 3 by 18 that is 54 then subtract 72 by 54 which gives you 18 then divide 18 by 6 which is 3

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.