Answer:A
Step-by-step explanation:Only one that makes sense
Let's list what we know.
We know 6 + d is the same as 21
We can use this.
6+d=21
Subtract 6 from both sides
d=15
So d=15
Answer:
Unicorn a : 1,160, and Unicorn b : 290
Step-by-step explanation:
We can make this an equation
Unicorn a is 4x
Unicorn b is x
4x + x = 1,450
x = 290
Unicorn a : 4•290= 1160 years old
Unicorn b : is 290 years old