The 10 tons should have 37.9% cement.
Let the 25% mixture be x tons
Then the 68% mixture will be (10 -x) tons.
Using formula for mixtures:
Let p for percentage and w for weight in tons.
p₁w₁ + p₂w₂ = pw
25*x + 68*(10-x) = 37.9*10
25x + 680 - 68x = 379
680 - 43x = 379
680 - 379 = 43x
301 = 43x
43x = 301
x = 301/43
x = 7
Recall that x, was for the 25% mixture, 7 tons.
a) For the 68% mixture, = 10 - x = 10 -7 = 3 tons.
b) For the 25% mixture = x = 7 tons.  
        
             
        
        
        
Answer:
Could you put this in english so that i'm able to answer..?
Step-by-step explanation:
 
        
             
        
        
        
The best estimate for 1,374 is 1,400 and the best estimate for 6 is 10. This is because anything that is 5 and above you change it. Example: 16 the best estimate for 16 is 20 because 6 is above 5. And when a number is 4 and below you change the number below. Example: 12 the best estimate for 12 is 10 because 2 is below 4. And when the number is perfect like 10, you can keep the number the same. Example:10,20,30,40,50,60etc. 
Hope this Helped! :)
        
             
        
        
        
Answer:
15×2x
Step-by-step explanation: