If I have $500 in the 1st month and I divide it in 5 parts and invest it in 5 different on total the next month I get double the profit Everymonth this happens I take ¼ of the money for my needs and invest the ¾ If I started at the age of 10 and stopped at 40 how much money will I have that time​

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.

b is the right answer

once you solve it out the value of x is 13