Answer:
2
Explanation:
A 14 seater matatu makes 1420 = <<1420=280>>280 shillings per trip during normal hours.
It makes 1430 = <<1430=420>>420 shillings per trip during rush hours.
Since the matatu made 10 trips and earned 3540 shillings, then it made 10-3540/280 = <<10-3540/280=12>>12 trips during normal hours.
This means it made 10-12 = <<10-12=2>>2 trips during rush hours. Answer: {2}.