ABACUS International Math Challenge
for
3rd and 4th graders
December, 2004
A.457. There are two kinds of donuts on
a plate: some are filled with vanilla custard cream, others are filled with
chocolate cream. Without looking you have to take 11 of them to be sure
that at least one of those you took is filled with chocolate, and you have
to take 16 of them to be sure that you have at least one of each kind. How
many of each kind of donuts are there on the plate?
A.458. At a sleep over party the mother
of the host child put a few slices of cake on the table. If she put 8 more
slices on the table two more times then every one of the 15 children in
the room could have 3 slices each. How many slices did the mother put on
the table the first time?
A.459. At Halloween the costume of the
Witch was so good that hardly anybody could figure out who was wearing it.
Listen to what the children had to say:
Agnes: "I do not think Eva was the Witch."
Kate: "It was Agnes."
Judy: "I am sure it was Eva."
Eva: "It was not me."
Who was the witch if only one out of the four girls said the truth?
A.460. Children are sitting in a room waiting
for their performance to begin. Besides the children there are only 4-legged
chairs in the room. Every child is sitting on a chair alone. How many empty
chairs are there in the room if you can count 20 heads and 120 legs?
A.461. 7 boys and 5 girls signed up for
a dance competition. At least how long will this competition take if every
girl dances a full song with every boy, and a song is 5 minutes long in
average?
A.462. A class decides to decorate its
classroom, and the children want to collect the money for it. If everybody
gives in $1.50 then 95 cents will be missing. If everybody gives in $1.60
then they will have $1.15 left over. How many children are there in the
class and how much money is need for the decorations?
A.463. In the 4th grade play the children
danced and sang. Three times as many children sang as danced. Six children
did both singing and dancing. Three children did not participate in the
play. How many children did singing only if there are 29 children in the
grade?
A.464. In a Halloween costume competition
each participant was given a 3-digit number which did not have a digit greater
than 6, and the digit in the hundreds' place is the sum of the two other
digits. How many children participated the most if every participant received
a different number?
Please, send your solutions to: