Answer: 56 seconds or less
Step-by-step explanation:
3(46 + 52 + 54) [tex]\leq[/tex] 400 - x
Combine
3(152) [tex]\leq[/tex] 400 - x
Simplify
456 [tex]\leq[/tex] 400 - x
Subtract 456 from both sides
0 [tex]\leq[/tex] -56 - x
Add x to both sides
x [tex]\leq[/tex] 56 seconds