B is consider to be the y-intercept. If you plot those two points and draw a line connecting the two. The line would go through (0,14). Making 14 the y-intercept and the correct answer.
To work out the probability of both errors occuring, simply multiply the probability of the first error by the probability of the second error. Therefore the probability of both errors occurring is 0.2 * 0.3 = 0.06.
Solution:
Principal =P= $ 7,500
Option A→(Simple interest)
Rate of interest= R=4%
Time(
)=4 years
Time(
)=6 years
Amount= Principal + Interest(Simple or compound interest)
Formula for Simple interest


Total amount after 4 years when interest is simple= 7500 +1200= $ 8700
Total amount after 6 years when interest is simple= 7500 +1800= $ 9300
Option B
Formula for amount(A) when interest is 3.15% compounded annually.



Total amount after 4 years when interest is compounded annually=$ 8491 (approx)
Total amount after 6 years when interest is compounded annually=$ 9034(approx)
Half of a dozen is 6. And 12+12 is 24 and 24+6 is 30. So Katoni bought 30 pencils.