Given:
Cost of two donuts and three cookies = $3.30
Cost of five donuts and two cookies = $4.95
To find:
The cost of each donut.
Solution:
Let x be the cost of each donut and y be the cost of each cookie.
Cost of two donuts and three cookies = $3.30
...(i)
Cost of five donuts and two cookies = $4.95
...(ii)
Multiply equation (i) by 2.
...(iii)
Multiply equation (ii) by 3.
...(iv)
Subtracting (iii) from (iv), we get
Divide both sides by 11.
Therefore, the cost of each donut is $0.75.
Answer:
option B
Step-by-step explanation:
For the first digit you are choosing from 2 digits
for the second digit you are choosing from 2 digits
for the third digit you are choosing from 2 digits
2*2*2=8
111
110
011
101
000
001
100
010
However......
A number doesn't usually start with a 0 or 0s.
Therefore, if you want 3-digit numbers and not just permutations using 0 and 1, then you must eliminate
011, 000, 001, and 010
Seeing that the first digit can't be 0, you choose from 1, then 2, and then 2 digits again; 1*2*2=4 numbers
You choose which answer best suits your problem.
MP
PM
Assuming your n is on a side