Jennifer is upset because she confused the two close readings that she

Question

Jennifer is upset because she confused the two close readings that she took for the period of a simple pendulum. She needs to find the average of the two readings. What is the exact average of the two readings?

(1) She knows that the second reading is one of the numbers 3.02 and 3.2.

(2) She knows that the greater reading is one of the numbers 3.01 and 3.11.

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GMATinsight · Answer

Question: Exact Average of two readings = ?

Statement 1  : She knows that the second reading is one of the numbers 3.02 and 3.2.
 NOT SUFFICIENT

Statement 2  : She knows that the greater reading is one of the numbers 3.01 and 3.11.
 NOT SUFFICIENT

Combining the statements

First smaller value must be 3.02 as other value has to be greater and that must be 3.11 therefore average can be calculated
 SUFFICIENT

Answer: Option C

Related Video:

https://www.youtube.com/watch?v=meIcqs4YHgs

ManifestDreamMBA · Answer

Interesting question

Avg = (Reading1+Reading2)/2

Need values of Reading1 or Reading2 or their sum

Statement 1
Reading2 = 3.02 or 3.2
We don't know anything about reading1
Insufficient

Statement 2
Reading 1(greater) = 3.01 or 3.11
We don't know anything about reading2
Insufficient

Combined, we have 
Reading2 = 3.02 or 3.2
Reading 1(greater) = 3.01 or 3.11
Reading 2 is smaller and hence, cannot be 3.2, which is greater than both reading1 values
Reading 2 = 3.02
Reading 1 = 3.11 (as it is greater than 3.02)
Answer C

sujoykrdatta · Answer

We need to know the readings

Clearly, each statement alone is insufficient since neither alone gives a complete information about both readings

Combining: 
We know from (2): the greater reading is one of the numbers 3.01 and 3.11
And from (1): one of the readings is 3.02 or 3.2

From (2), if we assume that the greater reading is 3.01, then statement (1) becomes false since both 3.02 and 3.2 are greater than 3.01 which we assumed to be the greatest.

Thus, the greater reading must be 3.11
Hence, from (1), the other reading must be 3.02 (smaller than 3.11)

Since the readings are 3.11 and 3.02, the average can be calculated.

Ans C

Dereno · Answer

We need to find the exact average of the two readings.

Statement 1:

(1) She knows that the second reading is one of the numbers 3.02 and 3.2.

This statement standalone is not sufficient.

Statement 2:

(2) She knows that the greater reading is one of the numbers 3.01 and 3.11.

This statement standalone is not sufficient.

Combining statements 1 and 2, we get

let’s take statement 2, first for consideration, we have two cases 3.01 and 3.11

if the greater reading is 3.01 , then statement 1 has values 3.02 and 3.2 which are greater than 3.01. So, cannot be correct.

Thus, the greater reading can be 3.11. Now, what’s the other reading ? Can we infer it ?

if we compare 3.11 with 3.02 and 3.2, we can neglect 3.2 ( greater than 3.11). Leaving us with 3.02.

So, the two values are 3.11 and 3.02 . We can arrive at the exact average.

Hence,  Option C

Abhiswarup · Answer

We want to know the 2 missing readings which has been recorded incorrectly.

(1) She knows that the second reading is one of the numbers 3.02 and 3.2.

We come to know only one number and that is also not decided. Insufficient.

(2) She knows that the greater reading is one of the numbers 3.01 and 3.11.
We come to know only one number and that is also not decided. Insufficient.

Combing both
option 2 greater reading should be 3.11 otherwise no no can be selected from statement 1.

Similarly if greater no is 3.11 using statement 1, other no. is 3.02.

Answer is C.

Jennifer is upset because she confused the two close readings that she

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GMAT Data Sufficiency (DS) Questions

Jennifer is upset because she confused the two close readings that she

Prep Toolkit

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