A boy has 3 pairs of trousers, 2 jackets, and 5 shirts. How many different combinations of trousers, jackets, and shirts can he put together?
A 3-digit number in base 7 is also a 3-digit number when written in base 6, but each digit has increased by 1. What is the largest value which this number can have when written in base 10?
Mr. Bee moderators 24/09/2018 at 03:01
When written in base 7, the number is a.72 + b.7 + c
When written in base 6, the number is (a+1).62 + (b+1).6 + c +1
We get: a.72 + b.7 + c = (a+1).62 + (b+1).6 + c +1, it implies 13a + b = 43.
This yields a = 3, b = 4.
When written in base 10, the largest number possible: 3.72 + 4.7 + 9 = 184Quoc Tran Anh Le selected this answer.
A rectangle paper has the area is 8cm2 . If the length is twice the width, find the measure of the width ?
Huy Toàn 8A (TL) 15/09/2018 at 06:19
Let x, y be the length and width of the rectangle:
We have :
So the rectangle width is 2cmHuỳnh Anh Phương selected this answer.
Dương Đào Xuân 03/10/2018 at 14:00