Number of multiples of 7 up to 1337:

Number of multiples of 11 up to 1337:

Number of multiples of 77 up to 1337:

This means there are

distinct multiples of 7 *or* 11 up to 1337.
The sum of these multiples is

which can be computed using the well-known formula,

So you have
What seems to be the issue?
X+y=15
2x+3y=37
15-x=y
2x+3(15-x)=37
2x+(45-3x)=37
2x-3x+45=37
-1x=-8
x=8
x is the amount of bikes, so there are 8 bikes. 8x2=16.
37-16=21
21/3=7
There are 7 tricycles.
67 + 23 = 90
Because this pair of angles adds up to 90, they are complementary angles.
Hope this helps!! :)
The distribution of the possible digits of the numbers are
1.) 9, 9, 9, 9, 3 [Number of arrangements = 5! / 4! = 120 / 24 = 5]
2.) 9, 9, 9, 8, 4 [Number of arrangements = 5! / 3! = 120 / 6 = 20]
3.) 9, 9, 9, 7, 5 [Number of arrangements = 5! / 3! = 120 / 6 = 20]
4.) 9, 9, 9, 6, 6 [Number of arrangements = 5! / (3! x 2!) = 120 / 12 = 10]
5.) 9, 9, 8, 8, 5 [Number of arrangements = 5! / (2! x 2!) = 120 / 4 = 30]
6.) 9, 9, 8, 7, 6 [Number of arrangements = 5! / 2! = 120 / 2 = 60]
7.) 9, 9, 7, 7, 7 [Number of arrangements = 5! / (3! x 2!) = 120 / 12 = 10]
8.) 9, 8, 8. 8, 6 [Number of arrangements = 5! / 3! = 120 / 6 = 20]
9.) 9, 8, 8, 7, 7 [Number of arrangements = 5! / (2! x 2!) = 120 / 4 = 30]
10.) 8, 8, 8, 8, 7 [Number of arrangements = 5! / 4! = 120 / 24 = 5]
Number of 5 digit numbers whose digit sum up to 39 = 5 + 20 + 20 + 10 + 30 + 60 + 10 + 20 + 30 + 5 = 210