Mixture problem.
Ratio of 20% : 50% acids
=50-39 : 39-20
=11:19
total volume
=400L
vol. of 20% acid=400*(11/(11+19)=400*(11/30)=146.667 L
vol. of 50% acid=400*(19/(11+19)=253.333 L
Alternatively, use c=volume of 20%, d=vol of 50%
then
0.2c+0.5d=400*0.39
Since c+d=400, we have
0.2c+0.5(400-c)=400*0.39=156
solve for c:
0.3c=44
c=146.667 and d=400-c=253.333 as before.
Answer:
11042
Step-by-step explanation:
since it says "in all" that means u have to add them up
6,836 + 4,206 = 11,042
The answer would be about 89%
to solve this problem first you would have to subtract 4 from 36 to get 32 because you want to know how many she got right first .
so you put 32 over 36 ( the number she got right over the total number of questions ) and n ( the number you don't know yet ) over 100 . that will be the percent .
next all you have to do is cross multiply 32 times 100 and 36n , to get 3200 and 36n .
now you have to divide 3200=36n by 36 so you get n by its self but you have to divide on both sides of the equal sign .
when you divide you will then get 88 with a lot of remainder 8's so you would just round up to 89 .
finally you know n = 89% so she got 89% of her questions right .
