Answer:
Student can obtain 15 marks by attempting 8 questions.
Step-by-step explanation:
This question is incomplete; complete question is here.
A student taking a test consisting of 10 questions is told that each questions after the first is worth 2 marks more than the preceding question. If the third question of the test is worth 5 marks.What is the maximum score that the student can obtain by attempting 8 questions?
A students when attempts the questions the sequence formed by the scores he gets will be in the form of a, (a + 2), (a + 4), (a + 6)........
Which will be an arithmetic sequence with a common difference = 2
We know explicit formula of an arithmetic sequence is
Where = First term of the sequence
a = first term
n = number of term
d = common difference
It is given that 3rd term of this sequence is 5.
a = 5 - 4 = 1
Explicit formula for the sequence will be
Now if the student attempts 8 questions then from the explicit formula
Therefore, student can obtain 15 marks by attempting 8 questions.