Answer:
Let x represents the week and y represents the seashells
As per the statement:
Dora has 10 seashells and plans to add 2 shells every week.
"2 shells every week" means 2x
⇒y = 10 + 2x
It is also given, Jerri has 4 seashells and plans to add 5 shells every week.
"5 shells every week" means 2x
⇒ y = 4 + 5x
The system of equation would be used:
y = 10 + 2x
y = 4 + 5x
Since, the girls have the same number of seashells
⇒
Subtract 4 from both sides we get;
Subtract 2x from both sides we get;
Divide by 3 both sides we have;
x = 2 weeks.
Therefore, the number of weeks would it be before the girls have the same number if seashells is, 2 weeks.