We should find the number of possible ways the student can arrange 4CD from total 20 CDs. We should find the number of combinations.
Combination is a way of selecting r items (CDs) from a set (collection) of n items (CDs). The order of selection of the items does not matter in this situation.
In our case: r=4 , n=20
The formula is: C=n!/(n-r)!*r!=20!/16!*4!=20*19*18*17*16!/16!*4!=20*19*18*17/4*3*2=116280/24=4845
Answer:
1
Step-by-step explanation:
5m + 9n
5(-7) + 9(4)
-35 + 36
1
Answer:
A
Step-by-step explanation:
Answer:
<em>$18.40</em>
Step-by-step explanation:
(find the tip)
$32 x 15% = $4.80 (tip)
Total bill:
32 + 4.80 = 36.80
Each girl paid:
36.80 / 2 = $18.40
Answer:
Step-by-step explanation:
The trick here is when do the discounts take place? The "buy 1 get 1 half off" must take place before the total is computed to get the 20% off.
So she spends
First pair of socks: 20
Second Pair: 20 - 10 = 10
Hoodie: <u> 20</u>
Total: 50
Now she gets another 20% off which means that she still pays 80% of her purchases. (80 / 100) * 50 = 4000/100 = 40 dollars which is ultimately what she spent.
She saved a total of 10 + 10 = 20 dollars.
The % discount is (20 / 60 (which is what she should have paid) ) * 100
The % discount = 1/3 * 100 = 33.3 %