5x + 20 = 90 - a = 90 - (3x + 40)
5x + 20 = 90 - 3x - 40 = 50 - 3x
5x + 3x = 50 - 20
8x = 30
x = 30/8 = 15/4
b = 3(15/4) + 40 = 45/4 + 40 = 51.25
The measure of a supplementary angle is 180 - 51.25 = 128.75
Answer:

Step-by-step explanation:
As given
if n erasers have a weight of 80 grams .
I.e
n erasera = 80 grams.
1 erasers weight .

Now find out the weight of the 50 erasers.

Simplify the above

