Answer:
9 = n
Step-by-step explanation:
12 = 6(n – 7)
Divide by 6 on both sides
12/6 = 6/6(n – 7)
2 = n-7
Add 7 to each side
2+7 = n-7+7
9 = n
<h3>Answer:</h3>
2/15
<h3>Explanation:</h3>
There are 8C2 = 28 ways to choose 2 dimes from the 8 dimes in Annie's purse. There are 21C2 = 210 ways to choose 2 coins from the 21 coins in Annie's purse.
Of the 210 ways to choose 2 coins, 28 of the choices will result in 2 dimes being chosen. The probability of choosing 2 dimes is 28/210 = 2/15.
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<em>Comment on nCk</em>
The number of ways to choose k objects from n, when order does not matter, is ...
... n!/(k!(n -k)!)
For the computations above, we have ...
... 8C2 = 8·7/(2·1) = 28
... 21C2 = 21·20/(2·1) = 210
Answer:
Missing constant: 100
Step-by-step explanation:
perfect square (a - b)^2 = a^2 - 2ab + b^2
In this case
20x = 2 * x * 10
and
10^2 = 100
so
(x - 10)^2 = x^2 - 20x + 100
John and Paul want to go to the cinema, they know that the ticket costs $1 and each food box cost $3. If they spent $14, how many food boxes did each of them buy?
In this case since there is two people, we include that 2. 3x is representing the cost for buying x food boxes and 1 the cost for the ticket. 14 is the total amount of money spent.
Each of them buy 2 food boxes.
