PLEASE HELP ME AND SHOW YOUR WORK :)

1.5 x

Step-by-step explanation:

Ok so what you want to know before you start this is that 1.25 x10^6 is really

1250000 you just move the decimal place 6 places back; if it was a -6 you would move the decimal place 6 places forwards.

1,250,000+ 250,000 = 1,500,000

then to convert back to  scientific notation just move to the first number and place the decimal then count the zeros.

EX:

1.500000 --count zeros + the 5 because you moved the decimal in front of it too, and you are left with =

1.5 x 10^6

36 girls

step-by-step explanation:

the 48 boys is 4 parts of the ratio

divide 48 by 4 to obtain one part of the ratio

= 12 ← 1 part of the ratio

3 parts = 3 × 12 = 36 ← number of girls