Solution:

This is simply the numbers 2^0,2^1,2^2 ... that is 1,2,4,8,16... So for making 1000 kg we need up to 1, 2, 4, 8, 16, 32, 64, 128, and 512

Solution:

143547

Solution:

2519

The number has to end in 9.
Looked brute force for small numbers.
59 and 119 were promising, but no cigar.

Then looked for agreement among
39 + multiples of 40,
69 + multiples of 70 and
89 + multiples of 90
Smallest one was 2519.

Solution:

18 x 12 ÷ 2 + 3 = 111

Solution:

5625

n^1
75 * 75 = 5625 (sum of first 75 odd numbers).
50 * 50 = 2500 (sum of first 50 odd numbers).

Solution:

.05

Given the equation 8/x = 160, when you solve for x, you indeed get:

8/x = 160

To find x, you can simply invert the fraction:
x/8 = 1/160

Now, to isolate x, multiply both sides by 8:
x = 8 * (1/160)
x = 8/160
x = 1/20 = 0.05

Solution:

15

Solution:

1 or -1

Solution:

1 2 and 3

Explanation:
1 + 2 + 3 = 1 * 2 * 3 = 6

Solution:

14