ABACUS International Math Challenge
for
5th and 6th graders
September, 2002
B.321. 2/3 of a group of people are sitting
on 3/4 of the chairs in the room. At least how many people are there in
the group?
B.322. Six people are estimating how many
balls there are in a box. The guesses are: 52, 59, 62, 65, 49, 42. Nobody
guessed it right, and the differences between the guesses and the actual
number of balls are: 1, 4, 6, 9, 11, 12. How many balls are in the box?
B.323. One day 12 children from a class
went to see a movie. On another day 9 children from the same class went
to see a puppet show. 5 children attended both programs, and 10 children
from the class did not go to either program. How many children are there
in the class?
B.324. An analog clock is 15 minutes late
every day. The clock shows the exact time on January 1st, at noon. Which
day will the clock be exact at noon again for the first time?
B.325. We put down 8 identical squares
on a table one after the other. The one marked with the letter A is on the
top. The others are partially covered, only some parts of them can be seen.
In what order did we put them down?
B.326. A school wants to rent a bus for
a trip. They narrowed their choices to two options: one company asks $350
for the bus each day, plus $2 for every mile. The other company wants $300
for the bus every day but $2.50 for every mile. How can they decide which
company the school should choose?
B.327. Now it is 11 o'clock in the morning
(11 am). What time will it be 2002 hours from
now?
B.328. It takes a train 45 seconds to go
through a 1320 meters long tunnel, and 15 seconds to pass a post after the
tunnel. How long is the train?
Please, send your solutions to: