import Mathlib

set_option maxHeartbeats 0

open BigOperators Real Nat Topology Rat

theorem mathd_algebra_342
  (a d: ℝ)
  (h₀ : ∑ k ∈ (Finset.range 5), (a + k * d) = 70)
  (h₁ : ∑ k ∈ (Finset.range 10), (a + k * d) = 210) :
  a = 42/5 := by sorry