let the first number be x and the second number be y

then according to question

x is 1 less than y, that is

x=y-1   equation 1

also, twice of second number (that is 2y) is 20 less than four times first(4x), that is

2y=4x-20 equation 2

multiply equation 1 by 2, we get

2x=2y-2

2y=2x+2  equation 3

from equations 2 and 3

4x-20=2x+2

2x=22

x=11

from equation 1

x=y-1

11=y-1

y=12

CHECK

11 is one less than 12

twice of y, that is 24 is definitely 20 less than 4 times x, that is 44.

answers: first number is 11 and second is 12