a weights m kg,b weight is 20 kg less than three times that of a. If their total weight is 100 kg. Find the weight of a

30kg

Step-by-step explanation:

what we know is that 3a - 20kg is b. and if a + 3a -20kg = 100kg, it becomes algebra .

So, we move it over to the sides:

4a = 120kg

(here i moved -20kg to the 100kg and did the reverse. I also added the a's)

which means a = 120kg divided by 4

a = 30kg

It's the top left because the line passes through 10 on the y axis.