Problem Solving Skills for Mathcounts Competitions
Book Store => Twenty Mock Mathcounts Sprint Round Practices => Bookstore => Twenty Mock Sprint Tests Solutions => Topic started by: yongcheng3315 on January 21, 2014, 09:01:13 AM

TEST 2

For #28, could you explain in more details? I don't understand what the following means:
"Let the sum of the digits of a be 11x. Then the sum of the digits of b will be 11x + 1 + 1 –
9y = 11x + 2 – 9y (y is the number of carries of the sum of a and 11)."
For #29, I think you forgot to state that when both Alex and Bob increase their speed by 2km per hour, they'll meet in 6 hours.

29. Alex walks from village A and Bob walks from village B toward each other starting
at the same time. They meet in 8 hours. If each person increases the speed by 2 km per
hour, they will meet at the point 3 km away from the middle of the distance AB in 6
hours. What is Alex’s speed if he walks faster than Bob? Express your answer as a
decimal to the nearest tenth.

solution