The first thing we have to do to solve this is to formulate equations that led us solve for the number of text each member of the group sent. By calling K, D and H to the texts sent by Kala, Deandre and Hans respectively, we can start writing an equation for the total number of texts, which was 104, the messages sent by each member of the group must add up to 104then we can write:
K + D + H = 104
We are also told that Hans sent 3 times as many messages as Kala, then the number of messages sent by Hans must equal the messages sent by Kala multiplied by 3 and we can write the following equation:
H = 3K
Lastly, we are told that Deandre sent 9 more messages than Kala, then the messages sent by Deandre must equal the messages sent by Kala added to 9 and we can write the following equation:
D = K + 9
By replacing 3K for H, K + 9 for D in K + D + H = 104, we get:
K + D + H = 104
K + (K + 9) + 3K = 104
From this equation we can solve for K like this:
K + K + 9 + 3K = 104
5K + 9 = 104
5K + 9 - 9 = 104 - 9
5K = 95
K = 95/5
K = 19
Then, Kala sent 19 text messages. In order to find the messages sent by the other members of the group we just have to replace 19 for K in H = 3K and D = K + 9, then we get:
H = 3(19) = 57
D = 19 + 9 = 28
Summary
Number of text messages Kala sent: 19
Number of text messages Deandre sent: 28
Number of text messages Hans sent: 57
