C = # of carpenter hrs , b = # of blacksmith hrs
c + b = 30...c = 30 - b
20c + 25b = 690
20(30 - b) + 25b = 690
600 - 20b + 25b = 690
-20b + 25b = 690 - 600
5b = 90
b = 90/5
b = 18 <== hrs worked as blacksmith
c + b = 30
c + 18 = 30
c = 30 - 18
c = 12 <== hrs worked as carpenter
        
             
        
        
        
Answer:    RQ= 8.99 ( approx)
Step-by-step explanation:
Let MR= x
Since, In triangle, PRQ, tan 75°= 
⇒ RQ=  
Now, In triangle MRQ,
tan 60°= 
⇒ RQ=  
On equating both values of RQ,

⇒
⇒
⇒
⇒
⇒ ≈15.60
≈15.60
Thus RQ=8.99999999999≈8.99 
 
        
             
        
        
        
19/25 * 100 = 1900/25 = 76 ....numbers greater then 15
7/50 * 100 = 700/50 = 14....numbers less then 15
100 - (76 + 14) = 100 - 90 = 10 <== numbers equal to 15
        
             
        
        
        
X + (x + 10) = 154
2 x + 10 = 154 
2 x = 154-10 = 144
x = 72 (ans)
Not sure if it’s right 
        
             
        
        
        
Answer: 3
Step-by-step explanation: