0+ u(t) = f (t, u(t), D β+1 0+ u(t), D β 0+ u(t)), 0 < t < 1, u(0) = u (0) = 0, u(1) = 1 0 u(t) dA(t), where C D α 1-is the left Caputo fractional derivative of order α ∈ (1, 2], and D β 0+ is the right Riemann-Liouville fractional derivative of order β ∈ (0, 1]. The coincidence degree theory is the main theoretical basis to prove the existence of solutions of such problems.