His average speed is 2.27 meters per second
The student had a 40% error estimate
A: {<u>1</u>, 2, 3, <u>4</u>, 5, 6, <u>7</u>, 8, 9, 10, <u>11</u>, 12}
<span>B: {-2, -1, <u>1</u>, <u>4</u>, <u>7</u>, <u>11</u>}
</span>A<span> ∩ </span>B = {1, 4, 7, 11}
So the answer is B.
Intersection of two or more sets cointains only common elements.