Answer:
He added all the numbers as they were a decimal number, with the kilometers traveled by Bus and Car being 2 to the left than where it should have been.
How I found it:
Converting 7 and 2.3 into a decimal with the decimal place two to the left.
7 becomes 0.07
2.3 becomes 0.23
I added this to the kilometers traveled by train(which is 19.955km).
19.955km + 0.023 + 0.07 = 19.985
19.985 being the value for answer A.
Hope that helps :)
