Assuming LCD means Lowest Common Denominator
Assuming by "and" you mean adding the two
Well, you go by the multiples of 7;
7, 14, 21, 28, 35, 42, 49, 56, 63,<u> 70</u>
Multiples of 10;
10, 20, 30, 40, 50, 60, <u>70</u>, 80, 90, 100
Straight away you can see the lowest common multiple is 70,
Now to go about adding them,
2/7 * 10 (both sides) , 20/70
9/10 * 7 (both sides) , 63/70
Then you add the two; 20/70 + 63/70 - now we can add them because they share the same denominator
20/70 + 63/70 = 83/70 = 1 whole 13/70 (simplified)
<u>The LCD is 70
Quick tip, </u>to find a common multiple (not necessarily the lowest) multiply the two denominators.
Mode: 3 as it comes up the most
The answers A and C contain correct information but both of them provide different advice. so the answer is literally your opinion between a and c
Take the perimiter, subtract the bottom and divide by two