2. The sequence, formed from the sequence of primes by rounding each to the nearest ten, begins $0,0,10,10,10,10,20,20,20,30, \ldots$.
When continued, how many terms in this sequence are equal to 40 ?
A 1
B 2
C 3
D 4
E 5
Solution $\square$
The integers that round to 40 are those in the range from 35 to 44 .
The primes in this range are 37,41 and 43 .
Therefore there are 3 primes that round to 40 .