5(5a+b)-13
You would have to distribute
5*5a=25a
5*b=5b
B is the answer I believe, you’ve already combined like terms now you need to do that step.
My guess is that the exact answer would be $2544.75 because you would first multiply 2900 by .0675 to get 195.75. Then you would multiply that by 13 to get 2544.75.
So, first lets define our variables:
let x = the number of dimes
let y = the number of nickels
so our first equation would be x+y = 16
Since dimes are 10 cents and nickels are 5 cents the next equation would be as follows:
.10x+.05y = 1.35
now change the first equation so y = -x+16
now substitute:
.10x+.05(-x+16) = 1.35
then multiply so you get .10x+-.05x+0.8=1.35
combine like terms and you get .05x+0.8 = 1.35
then subtract 0.8 from both sides and you get .05x = 0.55 then subtract
and you get x = 11 then substitute 11 for where x should be and you should get y = 5
So, you have 11 dimes and 5 nickels
Answer:
25 milliliters of 25% solution and 75 milliliters of 5% solution should be used.
Step-by-step explanation:
Since the druggist has to prepare 100 ml of a 10% solution, but has only 5% and 25% solutions, to determine the proportion of each solution that he must use to prepare the solution with the desired percentage, it is necessary to perform the following calculation:
25 x 1 + 5 x 0 = 25
25 x 0.9 + 5 x 0.1 = 23
25 x 0.8 + 5 x 0.2 = 21
25 x 0.7 + 5 x 0.3 = 19
25 x 0.6 + 5 x 0.4 = 17
25 x 0.5 + 5 x 0.5 = 15
25 x 0.4 + 5 x 0.6 = 13
25 x 0.3 + 5 x 0.7 = 11
25 x 0.2 + 5 x 0.8 = 9
Therefore, the percentage that the druggist must use will be between 20% and 30% of the 25% solution, and between 70% and 80% of the 5% solution, that is:
25 x 0.25 + 5 x 0.75 = 10
Therefore, the druggist should use a 25% solution at 25%, and a 75% solution at 5%: Thus, since 100 x 0.25 is equal to 25, 25 milliliters of 25% solution and 75 milliliters of 5% solution should be used.