tanyajoseph wrote:How do u dedude to C^3 = 64???#
I get c^2 = 64. Could you help please explain how exactly you worked through?
Hi there ...
what answer do you come to here ? If in your calculation you say you get c^2 = 64, then this gives c a value of 8.
So if you Plug C = 8 back into the equation B = 8/C. So B = 1.
Which means b+c = 9 ... which is answer E ... which is incorrect.
Here's how I worked out the solution:
Step 1:
1/b = c/8
cross multiply to get bc = 8
so b = 8/c
Step 2:
Lets look at b/c = c/8
Plug in the value of b into this equation: (8/c)/c = c/8
This can be simplified (by cross multiplication) to read: (8/c)*8 = c^2
This can be simplified further to read: (8/c * 8/1) = c^2
which => 64/c = c^2
so 64 = c^3
so c = 4 (the cube root of 64)
Step 3:
From step 1 we got b = 8/c.
Now we know that c=4 ... we can get b = 8/4 = 2
Or we can just plug the value of c into the orginal numbers from the question:
1/b = b/ c
=> 1/b = b/4
cross multiply to get: b^2 = 4 ... so b = 2
Hence the answer to the queston: b + c => 2 + 4 = 6
We can check the answer by plugging these values b=2, c=4 into the original values from the question:
1/b = b/c = c/8
1/2 = 2/4 = 4/8
Hope this makes sense !
Best.
II
