30/2.5=12 i’m hoping that’s the answer you’re looking for:)
He could have wrote -2.5 or -3.
Answer:
Step-by-step expThe answer would be 18 because 36÷2 is 18.
Answer: 14.29%
Step-by-step explanation:
Let C be the cost of 1 article and S the selling price for 1 article. The profit, P, for 1 article would be:
P = S - C
For n articles, the total profit would be
nP = nS - nC
Profit percentage would be (P/S)*100%
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We know that 21C = 18S: This can be written as C = (18/21)S
P = S - C
P = S - (18/21)S
P = (3/21)S or P=(1/7)S
Profit percentage would therefore be
(P/S)*100%
((1/7)S/S)*100%
(1/7)*100%
= 14.29%
There are 
ways of picking 2 of the 10 available positions for a 0. 8 positions remain.
There are 
ways of picking 3 of the 8 available positions for a 1. 5 positions remain, but we're filling all of them with 2s, and there's 
way of doing that.
So we have
The last expression has a more compact form in terms of the so-called multinomial coefficient,
