If # means adding 9 times the second number to the first number, then (2 # 5) # 4 equals
Answer & explanation
Correct answer: option 3
The correct answer is Option (3) → 83
The rule is a # b = a + 9b. Work out the bracket first, then use its value as the first number of the second operation.
\(2\ \#\ 5=2+9\times5=47\)
\(47\ \#\ 4=47+9\times4=83\)