Answer:
76
Step-by-step explanation:
n a competitive exam of 40 questions, +3 is awarded for a correct answer and -1 for every wrong answer. Find the total score if a student had 11 wrong answers in his attempt of all questions.
Answers gotten wrong = 11
answers gotten right = 40 - 11 = 29
total score = (point for correct answer x number of correct answer) + (point for wrong answer x number of wrong answer)
(+3 x 29) + (-1 x 11) = 76
Answer: D. 
Step-by-step explanation:
Using exponent rules an exponent to the power of a number will multiply by each other.
So the -4 and -9 will multiply.
The 6 in the numerator will now have a positive exponent of 36.

Now we can divide and when we do so the exponents will subtract from each other.
So 36 - 6 = 30
And the base of 6 does not change.
The simplified form is 
They will have to buy all three items again in 9 years