What is the 57th term of the GP (geometric progression) whose first term is 5?
1) The second term of the sequence = 10
2) The third term of the sequence = 20
Let's assess the firststatement.
\( a_n = ar^{n-1}\)
\( a_2 = 10 = 5r^{1}\) . r = 2
Let's assess the secondstatement.
\( a_n = ar^{n-1}\)
\( a_3 = 20 = 5r^{2}\) .
\( r^{2} = 4\) .
Here, r may be 2 or r may be -2. Hence, it is not sufficient.
The answer is A (only statement 1)
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1) The second term of the sequence = 10
2) The third term of the sequence = 20
Let's assess the firststatement.
\( a_n = ar^{n-1}\)
\( a_2 = 10 = 5r^{1}\) . r = 2
Let's assess the secondstatement.
\( a_n = ar^{n-1}\)
\( a_3 = 20 = 5r^{2}\) .
\( r^{2} = 4\) .
Here, r may be 2 or r may be -2. Hence, it is not sufficient.
The answer is A (only statement 1)
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