A-2b=-10
add 2b on both sides
a=2b-10
add 10 to both sides
a+10=2b
divide both sides by 2
a/2+10/2=a/2+5=b
b=5+a/2
Answer:
30 mins
Step-by-step explanation:
<em>speed = distance/ time </em>
speed of car A
= 20/ 12 km/ min
= 5/ 3 km/ min
also, speed of car A = speed of car B
speed of car B = 5/ 3 km/ min = 50km / time taken (in mins)



=> t = 30 mins