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# Find the missing term 4, 9, 19, __, 79

Tue 6 Jun, 2017 02:58 am
Find the missing term 4, 9, 19, __, 79
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Type: Question • Score: 0 • Views: 451 • Replies: 5
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timur

1
Tue 6 Jun, 2017 05:01 am
World War II started that year...
Blickers

1
Tue 6 Jun, 2017 10:03 pm
@timur,
Depends what country you were in.

Anyway, each number is twice the preceding number +1.
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Kolyo

1
Tue 6 Jun, 2017 10:59 pm

First, you have to understand that the numbers are hexadecimal.
As such they are all perfect squares.
The sequence becomes 2^2, 3^2, 5^2, ____ , B^2.
2, 3, 5, 7 and B are the first 5 primes.
So the missing number is 7^2 = 31.

Kolyo

1
Tue 6 Jun, 2017 11:01 pm
@Kolyo,
If you have any other questions such as how far it is from Winnipeg to Montreal, or who the 31 steps are, i can't help with those I'm afraid.
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timur

1
Wed 7 Jun, 2017 12:48 am
@Kolyo,
Don't make it too complicated.

The missing number is 39 as the series is the double of the difference between two successive numbers.

9-4=5
19-9=10
39-19=20
79-39=40
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