Answer
$2435$
Work Step by Step
We are given that the sequence $ a_n $ is an arithmetic sequence and the sequence $ b_n $ is a geometric sequence.
Here, we have $ r=-2$ and $ d=-15$
The general formula to find the nth term of a Geometric sequence is given as: $ a_{n}=a_1r^{n-1}$
Thus, $ a_{10}=a_1r^{10-1} =(-5)(-2)^9 =2560$
The general formula to find the nth term of an arithmetic sequence is given as: $ a_{n}=a_1+(n-1) d $
and $ b_{10}=10+(10-1) (-15) =10-135=-125$
Now, $ a_{10}+b_{10}=2560-125=2435$
