1. Li has t toy bricks.
She only has red bricks and blue bricks. Li picks two bricks, one after the other.

If the first brick she picks is red, the probability that the second brick is red is $\frac{2}{3}$.

If the first brick she picks is blue, the probability that the second brick is red is $\frac{7}{10}.$

Calculate the value of t .

t = .........................................................