I think the last two are correct.
Hope it helps
Answer:
D) 50/3
Step-by-step explanation:
6/10 = 10/(6+x-6)
6/10 = 10/x
6x = 100
x = 100/6
x = 50/3

Hope you could get an idea from here.
Doubt clarification - use comment section.
Answer:
Lets say test tubes = t, and beakers = b
1 pack of (t) is $4 less than 1 pack of (b)
Since i have no prior information we are going to use variables for this equation:
1t (1 pack of test tubes) is $4 less than 1b (1 set of beakers)
so to quantify the equation, we have 8t and 12b.
if b is a number that IS quantifiable such as $5 we can easily figure out this answer.
Lets use and example that 1 set of beakers is $8, if we multiply $8 by 12 (the number of sets of beakers), we get: 96
Using the same example, if 1t is $4 less than 1b than 1t = $4. So, if we multiply $4 by 8 (the amount of packs of test tubes), we get: 32
If you take both of those numbers: 96, and 32 and you divide them you get 3. so that means that 1t = 3b
Answer = 1t = 3b
This may not be correct due to the little information that i got however i hope that, that works out for you :)
Answer: it is 14 thanks to the other person
Step-by-step explanation: