String a is 35 centimeters long. String b is 5 times long as string a. Both are necessary to create a decorative bottle. Find the total length of string needed for 17 identical decorative bottles.

string a is 35 cm.....string b is 5 times as long as string a.....
so string b is 5(35) = 175 cm....both are needed....
175 + 35 = 210 cm for 1 bottle

for 17 bottles...
17 * 210 = 3570 cm <== 3570 cm are needed for 17 bottles