The two isotopes of chlorine are 35/17 cl and 37/17cl. which isotope is the most abundant

The most abundant is 35/17 Cl

explanation

This is  because Chlorine  35/17 is the one close to the average atomic mass of chlorine which is  35.46 u making it to be the most abundant.

average atomic mass of chlorine is 35.46 + or- 0.02

16 + 8b ≥ 50

4500

Step-by-step explanation:

He needs at least 50 rooms and has already reserved 16

They are in groups of 8

16 + 8b ≥ 50

Subtract 16 from each side

16+8b-16 ≥ 50 -16

8b≥ 34

Divide by 6

8b/8 ≥ 34/8

b≥ 4.25

We need to round up since we need at least 50

b = 5 since we want the least amount of rooms

Each block is 900

5*900 = 4500 more that he will have to spend