A quick way to multiply 11*.818 is to split up the problem:
11* .818 = (10+1)*.818
= 10*0.818 + 1*0.818
10*.818 = 8.18
1* .818 = .818
10*0.818 + 1*0.818 = 8.18 + .818
= 8.998
With that being said, it's important to recognize that we don't have to calculate anything to answer the question. Given the information, you know that you could determine the exact values to see if a/b is < 9/11. Knowing that we can answer the question is enough to say the statement is sufficient :)
This is good to keep in mind in order to save time on DS questions!
Wouldn't we still need to calculate the exact values for each scenario, given that we would have to see if we could get a solid "yes" or solid "no", but not both, for each statement? For example, wouldn't we have to double check to make sure that any number that fulfills the inequality a/b < .818 is always EITHER < or > 9/11? same for (b).
In each of the two statements, we're given a single value that doesn't change. In other words, we know the value of either a/b or b/a. The relationship between the value from the statement and a/b is constant and will not change. So, we can be confident that the value provided will either satisfy the inequality or not. However, there's no need to determine whether the answer is "Yes" or "No." We simply need to determine that we could determine whether the answer is "Yes" or "No" for the individual statements :)
I hope this clears up your doubts! If not, please let me know :)
2 Explanations