Answer:
LCM = 10
Tanvi built at least 1 sandcastle with 10 towers, and Gina built 5 sandcastles with 2 towers each again making a total of 10.
Explanation:
This is found out by calculating the LCM. For finding the LCM we list out the factors and then multiply them to get the LCM.
Factors of 2= 2*1
Factors of 10= 2*5
Since 2 is common it will be used once and then multiplied by 5 will give the LCM
LCM = 2*5*1= 10
So the least number of towers built by each is 10.
Tanvi built at least 1 sandcastle with 10 towers, and Gina built 5 sandcastles with 2 towers each again making a total of 10.