Answer:
Two
Step-by-step explanation:
In multiplication problems, your answer can have no more significant figures than the number with the fewest significant figures.
Start with the calculation inside parentheses:
5.1 × 10.6 = 54.060 000 00 (by my calculator)
There are three significant figures in 10.6, but only two in 5.1.
In this were a number you had to report, you would round to two significant figures and report the answer as 54.
54.060 000 00 → 54 (to two significant figures)
However, you must multiply this intermediate answer by 2.524.
Therefore, you multiply the number in the calculator by 2.524 and get
54.060 000 00 × 2.524 = 136.447 4400
NOW, you round to two significant figures and report the answer as 140.