21/b = 147/105

Cross multiply and solve for b.

Is the answer 15. I am trying to help my grand daughter with her homework,

Yes. You're right. :-)

To find the value of b in the equation 21/b = 147/105, we can set up a proportion and solve for b.

We start by cross-multiplying:

21 * 105 = 147 * b

Simplifying:

2205 = 147b

Now, we need to isolate b by dividing both sides of the equation by 147:

2205 / 147 = b

Simplifying:

15 = b

Therefore, the value of b in the equation 21/b = 147/105 is 15.