
Multiply 4.8 into (20/3), and multiply 16/9 with (1.2b)

Multiply 9 on both sides
19.2b = 32(9)
19.2b = 288 Divide 19.2 on both sides
b = 15
If she gets 3% of what she sells you multiply the decimal form of the percent by the amount she has made:
50*.03=1.5
So she make $1.50 for every $50 of sales, so you multiply the amount she made by her commission each day by the number of days she worked:
1.5*30=45
She earned a total of $45<span />
<span>When order does not matter you use what is called n choose k formula
n!/(k!(n-k)!) where n is the number of things to choose from and k is the number of choices made, in this case:
20!/(4!(20-4)!)=4845</span>